For what purpose? The system uses a Bloomfield era Xeon which, these days, is better suited to home/office/youtube viewing or light workstation tasks than gaming.
Also, what power supply is installed? Workstation parts are, by nature, reliable but if it's the part the system was built with it'll be getting on by now and well past its best.
Finally, now is a really terrible time to purchase a GPU, prices are just plain crazy unless you get lucky.