cardio workouts for me.HELP??

hello,i started my new healthy life in july of this year.
ive lost alot of weight and i feel great and look great.
i dont know my exact weight but i was about 195 and now im guessing im around 165.

well in 2006 i had a bad injury with my left leg and i cut my main atery and have no feeling in that leg.
but i can walk and when that happend i was not active i was in the hospital and i gained lots of weight.
i wear a leg brace now.

When i started my diet i walked everyday bought the wii fit and eat healthy.
well since i cant do all of the cardio workouts i wish i could do like running,i cant.
im getting a YMCA membership soon and working out and swimming there.

i have a problem though.I have some stomcah fat still and i would like to tone it up so will someone give me some suggestions maybe on how to that doesnt involve and sort of hard leg exercises?

thanks:)

brooke,13