the GTX 470 is a powerful card, and we wouldn't want any bottlenecking to occur, because that won't bring out the full potential of that card! but yes, the board and card will work, not to its full reach, but will work!
why don't you overclock the CPU a bit? to at least 3.0- 3.2 Ghz? if you don't know how to do this, rahter not, because it can be dangerous if one doesn't know what their doing!!
in short, the system will work, but your next upgrade is CPU and motherboardfor maximum outbringing of that awesome card of yours!!
just my thought