For installing graphics cards please follow the link and open de MSM and try to install the right driver from the hardware detection option
If this process does not work for you this is the next step
If this does not provide the solution, please:
p.s. if you do want to go through installing manualy and want the headers you need to install linuxXXX-headers where XXX is the kernel version, eg if you have 510 installed this would be linux510-headers