question on adding a second cat

This is something that is not in my immediate future, but one day, I'd like to add a second cat to the household. My Girlkat seems to need more companionship than I can offer her, and the dog refuses all her attempts to get him to play with her.
A small concern of mine is how well she would adapt to adding a new kitten to the house (I would probably want a young cat, even though I understand that there are so many older cats that need homes. When it comes to animals, I really have baby fever. What can I say; I don't want human babies!). I am sure, though that Girl would adapt and learn to enjoy the company of a young boy cat.
My real concern, however, is this: Girlkat's first owner declawed her. I know, I know, it's a horrible thing to do, and I would never do it to a cat myself, but she needed a home, and it was my house or the pound, so I adopted her despite my (shameful) inner desire to punish her owner for having the surgery done in the first place. Girl needed a home, so I didn't take out her owner's sins on her. She had suffered enough just by having the surgery done in the first place, and then having to be rehomed (losing her first brother cat).
So the problem is that I wouldn't want her to be unable to defend herself when she starts scrapping with her new brother. What do I need to be aware of when adding a clawed cat to a house with a declawed cat? Should I just adopt another cat that has already been declawed (fat chance, I'm sure)? Or will the two of them work out the details without human interference?
Girlkat is 4 years old. Is 5 years old too hard of an age to be learning how to live with a brother? And a boy cat is a good decision, right? I mean, no one wants to put up with another hen in their henhouse. I've read that she'll have a better chance of getting along with a male than a female.

There are declawed cats with behavior problems. Is Girl one of them? If she is, it is unwise to get her a companion. It will stress her further and you will end up with more problems.

From my experience, introducing a male to an older female is better then another female. Most of the females I've had are more territorial about other females and much more accepting of a new male in the house.

As long has he's neutered and you keep his claws trimmed, there shouldn't be a problem with her being declawed. I'd look for a more laid back male.

I also find that females take to a male much better then another female. I would go with a kitten. As they don't have such sharp claws and want be aggresive and want to fight.I think your older declawed cat would do much better with a kitten compared to a older cat.

thanks for the advice guys. to answer your question, i don't think she's got behavioral problems. i'm not too experienced in the ways of cats, but she seems like a normal female from what i've seen. she definitely acts differently that the male cats i had growing up, but they were all indoor/outdoor cats, and (like i said) male. from what i've seen, female cats can be much more elusive than males.
she's had one semi-recent experience with another cat, but it wasn't a purposeful encounter. we were moving cross-country and stopped at my parent's house that my sister and her cat were temporarily staying at. i had been under the impression that my sister's cat was solely outdoor, so i was a bit surprised when my sister came home and brought her (extremely wily) cat inside and carried her upstairs. i decided to not make a big deal about it and just keep them seperated, but Girl must have caught a glimpse of Witchy because i heard a hiss and Girl came streaking down the stairs like a terrified bat out of hell. so as far as i know, she's scared of other female cats. or else, she just got a big fright.
she's pretty good with dogs. she senses right away whether she should be scared or not and acts accordingly. if it's a boisterous and nosy dog, she hides and if it's a dog that can respect her boundaries she'll be out and sniffing in no time.
she's not overly aggressive with any member of the household, but she is a very active female and likes to play aggressively. she does control herself in play, though.
does that sound like a behavioral problem?
and i guess you guys have said pretty definitively that a clawed male kitten would not be a problem?

I have rescued three cats. One is declawed and the other two aren't. They are all females. The declawed one hates the other two, probably out of fear. I realize her life isn't so great, she'd prefer to be an only cat, but all three of them would have been dead if they hadn't been rescued, so I can only do so much.

If I were you, I would not adopt a kitten, but an adult declawed cat, probably of the opposite gender. You will find LOTS of declawed cats needing homes after being given up on by stupid owners who mutilated them first and then got mad because the cat developed behavior problems. As you may have guessed, I believe the minimum penalty for declawing a cat should be amputation of the owner's fingers.

Keep one thing in mind - most of the declawed cats in the shelter are turned in for behavioral (biting) problems or litter box problems due to the declawing.

She should be safe with a clawed cat with a laid back personality.