It should be ok, but I would try to get atleast 500watts. If you plan to upgrade most of the new video cards will need 500watts, this way you dont have to buy a new psu later on..
yeah, you'll definitely be fine with 430w. if you will be upgrading that mediocre 6600 in the future, then yes, get at least 500w. but for now you'll be fine. and plus, you can always get a new psu