that's why they make programs that detect the heat generated by cards like this, and it's why the makers include software to assist in determining said heat. it's for people that are concerned with what it might be doing to their system and to the card itself.
it's nothing really to be afraid of. all it takes is doing some reading. read up on reviews, check for people that already bought it and have posted temperature readings. check for what is safest, and check for what is the easiest way of cooling it for the right price.
once you've done you're homework, make sure you're stocked on all the cooling you need, and slap the card in there and keep an eye on it. if it starts breaking your personal upper limit for heat tolerance, like say if you wanted it to stay below 40 C and it goes a few degrees over, then do as the OP is doing. if turning the fan up to a higher setting doesn't do the trick, buy a better fan. or an extra fan. or hell... if you feel like it, buy a water cooler or something.
an 8800gt was built to play games like bioshock. in fact, that was probably one of the benchmarks for how well it could perform. so i wouldn't be terribly worried. i don't think you're in any danger. but if you don't feel safe, then at least you know what to do.
the same goes for your power supply. if you've done you're hw, then you should know what's a good PSU, and what isn't, and which ones can handle varying degrees of stress.
if you want some reassurance, refer to this:
http://forums.firingsquad.com/firingsquad/board/message?board.id=hardware&thread.id=111309
it lists the more common PSUs from best to worst. if you've bought something from tier 3 or above, no need to worry. but if it isn't on the list, then just take a look at the wattage rating, and the price. if you got a 600watt psu for 50 dollars, be afraid. it will likely be low quality and will crap out very soon. if not immediately. generally, anything that is about 450-500 watts should've cost about 80 dollars. and any wattage higher, obviously should've cost more.