If you're planning on a monitor upgrade anyway, maybe you need a GTX560 (not the ti version). It's more than 160 across the board, but last you even after the monitor change.http://www.newegg.com/Product/Product.aspx?Item=N82E16814125345
If you're fixed to 150, that card will be plenty. That's clocked at 800Mhz and will also last.
Should be enough with the 450W PSU also. Without the details on 12V power, can't tell exactly though.
Anyway, keep browsing the GTX460's, because they fit your budget and res perfectly (lot's of options to choose from).