You will be able to play Just Cause 2 and Crysis 2 but don't go above lowest settings or your frame rate will be too low, I have played both games on a system much the same except with a GT 8800, a very budget card.
The 8800GT is actually a good deal more powerful than an HD 4350. It is available cheap due to being pretty outdated. The weakest 8800GT is about equal to an HD 2900 Pro or an HD 3850 256 MB. The 8800GT also meets the minimum system requirements of all those games. The 4350 does not meet minimum requirements for Crysis 2 or Just Cause 2.