Lyka, I have three cats and allergies (yes, I'm a sucker for stray cats and would rather deal with the allergies than see these babies outside
). Here are a couple things I do to keep my allergies from flaring up:
Vacuum! I vaccuum at least once a week, and the actual vaccum has a filteration system, which has be changed every couple months.
Change the air filter in your home to an allergy-reduction filter. This has really helped keep the dust/dander down in the house.
If the cat is allowed to sleep on the couch, use a lint brush on the furniture once a week or so and vacuum the cushions.
Don't let the cat in your bedroom (I'm bad about this, but only one of mine likes to sleep on the bed -- and I like having a kitty curled up with me, so I deal with it). If you do, change your linens at least once a week.
Also, I'm on a prescription allergy medicine too, Zyrtec, which has really helped with the cat allergies and all the other seasonal allergies.