With your budget amount these two are about the best that you can get and they will be fine for Skyrim and movies but for BF3 it will be a different story since that game is very video card demanding and you most likely get less performance. If you could increase your budget amount a little then you could get a better card.
That power supply is terrible 17A on the 12V rail and from a review "Casecom's ATX 500W is cheap and quiet, but it manages only 50 per cent of its claimed power output before its voltages wander." even if it could supply the 17A its rated at that makes it a 300W PSU max (Corsairs cheapest 430W has 28A on the 12V rail). Your power supply needs upgrading before you will be able to use any of the above recommended cards.