ATI Mobility Radeon HD 4570?

Right now I have a Fujitsu Lifebook N6460 with an ATI Mobilty Radeon HD 2600. I'm would like to upgrade it but I'm kinda in the dark about these kind of things. Can I put a ATI Mobility Radeon HD 4570 MXM Type A 5739G or ATI Mobility Radeon HD 4570 MXM Type A DDR3 in my Laptop? If not, are there any other video cards that I can upgrade to? Not really considering buying a new computer. Any help is appreciated. GO