If this is your kitty's FIRST heat, then it should be all over with in about 5 to 7 days - give or take a day or two. The actual rolling around, howling, etc., normally only lasts about 3 to 4 days, then you should notice her begin to taper off a bit.
I would hold off getting her spayed until she is finished with her cycle. The reason for this is because 1) there is an increased risk of bleeding and 2) there is always a risk in putting cats under anesthesia - why do it when there is a double risk?
Just make 100% absolutely certain she doesn't have access to the outside where she can become pregnant.
As for making YOU more comfortable, try confining kitty in a cool, dark room away from the general population of the house. The cooler temperature and absence of light will allow her discomfort to be lessened.
While I can 100% sympathize with you on this (I have Siamese - have you ever heard a Siamese female in heat?????), it won't last long and you all will be back to normal in a week or so.
If she isn't spayed when this cycle is over, she should cycle again in about 19 to 21 days give or take. But - given that this is kitty's first estrus, it may be another few months before she has another cycle.
Best of luck,