Confused on a few hands

[Mroberts3]

I just recently got really turned around in a pot that, even after some consideration, I am not sure what I should have done. I called from the button with 78s and hit top pair on a flop of 458. seems ok, but the problem was that the flop was 7 handed. with a bet from the BB and 5 calls I wasnt sure what to do. I mean I might have the best hand (maybe not) but in either case I will probably need to improve to win. Raising doesnt seem right(wont limit field, plush i dont have much equity), nor does folding (as I have top pair), but calling doesnt seem to be better than the first two options (because my outs might be tainted because someone could have top pair higher kicker or a str8 draw). Any thoughts or ideas? Thanks.