Hi Desiresgrasp! It's so wonderful of you to try to help this cat!
Please take hissy's advice about not using store-bought flea and tick products. Many people have used store-bought flea collars or baths only to have their cats die. They are very dangerous to the health of ANY animal, let alone a pregnant one.
I hope you are keeping this new kitty separate from your pets. Until she sees a vet, there's no knowing what illness or parasite she can pass along to them. Do not let her interact with them until a vet gives her a clean bill of health.
We do sympathize about not having the money to see the Vet. It has happened to all of us who rescue cats. They often seem to come along at the most inconvenient of times. When the mom with kittens turned up in our yard and we decided to trap and have neutered all the feral (wild) and stray cats around here (so we wouldn't have to deal with any more kittens), we called a local vet, spoke to them about our problem, and made arrangements to pay over time. They were very sympathetic to our needs, and wanted to help prevent further unwanted pregnancies. We were able to get all the cats vaccinated as well purchase proper and safe medication for ridding the cats of parasites.
I think the phonecall or two to one or more local vets is worth the time. It certainly can't hurt to try!
I also sent you an e-mail, so don't be surprised if you see something from someone at TCS!