I have a HP p6720f and it has onboard graphics. I am thinking of putting in a different video card. I really don't want to change out the psu right now. My PSU is like 250 watts or so. I am looking at this one http:// or http:// or this one http:// which one of those would be the best?
Save your money, none of those are going to perform much better than the integrated option on that system. Any card that would be worth the upgrade is going to require a PSU upgrade.
First of all, why are you looking to get a video card?
Because my laptop has better graphics then my desktop. Also a few games I have are hard to play on my desktop. So that is why I am looking. For a new video card.
If you want noticeably better gaming performance you're going to have to spend a little more than that, especially for any games from the past couple of years. You'll also need a new power supply as others have said.