The problem you're encountering (in addition to the fleas is that the cat is seeing the bath as a huge ball of stress and so are you, and you're both going into it as a conflict. If you can start your cat off slowly, and make the experience as pleasant as possible, you may be able to get the cat to learn accept bathing.
So for example, take the cat into the bathroom (or wherever the bath will happen) a few times without bathing them, so they don't immediately panic when they are in the bathing room. Give them their food in there with the water running, so they associate the sound with something good, or toss a treat in the tub so they can jump in and back out again a few times on their own and feel secure. That sort of thing.
Unfortunately with an adult cat that has already learned to hate baths this might take longer than you want to invest and honestly I am not sure if bathing is really the solution here anyway, given your specific problem.
Over the years I've come to rely on Advantage to get rid of fleas. Some people recommend other brands, but that's the only one that has worked reliably for me. It's a topical medication which you dose your pet with once a month.
is that the cat is seeing the bath as a huge ball of stress and so are you, and you're both going into it as a conflict. If you can start your cat off slowly, and make the experience as pleasant as possible, you may be able to get the cat to learn accept bathing. 
