Hmm..I think you'll be fine. I have a desktop GDDR3 5450 and I can play Crysis on mostly medium settings at 1280 x 800. A desktop 5450 should be similar to a 5470 laptop version. Since laptop screens are similar you could probably run both COD6 and SC2 at medium settings @ 1024 x 768 fairly smoothly since both those games shouldn't be more demanding then Crysis.
54xx series is good for multimedia and some light gaming, it's not that bad