I'm thinking of ordering a Dell inspiron 15, but what graphics card?

I'm thinking of ordering a Dell inspiron 15, but i've heard that the Intel Integrated GMA 4500MHD that comes with it is shocking, now i'm not really going to be doing much gaming on it, only really playing a few games, the most demanding possibly being gta san andreas or maybe even sims 2. So would it really be worth spending an extra �45 on a 256MB ATI Mobility Radeon HD4330, that is another option? My desktop at the moment uses an ATI RAdeon 9200, which seems very outdated, so i'm not expecting brilliant results just something that can run these games! Also would it be an option to get the integrated card and then if that didn't work replace it, or is that not an option if the card is integrated? thanks!