Yeah, in that case, adding the discrete graphics card should help your systems out.
"Cleaned Up" is a fairly wide open statement. It could mean anywhere from the mopped up the split cola on the outside of the case to they completely dusted the components and did a fresh install of Windows XP. Without them saying so, there's really no telling, but if they "cleaned" the systems properly and if they have 2GB of RAM installed, then you should not be experiencing the issues you are having.
The systems you have configured should not be having the issues you're experiencing. I suspect there are extraneous programs running in the background that are hogging up resources. With 2GB of RAM installed, I would suspect your processor just is not capable of handling the load. Either go into your Windows Startup Folder and remove all but what you need to kick off when you boot windows, or get a better processor.
With 2GB of RAM installed, I still think your better option would be to install a better processor. Your specific needs do not require a better graphics card. It would help, but not as much as a better processor.
-Wolf sends