@ Pyree - Model is in the thread title: HP Probook 4420s
@ aaronpj - Generally speaking, laptops with discrete graphic cards should not be upgraded beyond what's listed as options in the system specification. Heat and Power become issues and you could cause further damage to your laptop. Additionally, finding a better solution is usually difficult and ultimately not cost effective.
According to the specifications
of your laptop, the best you should place in there (assuming you can upgrade it), is the AMD Mobile HD 5470. If this is what is currently installed, I wouldn't suggest trying to upgrade.