Welcome to the Tom's Hardware forums!
Are the onboard graphics not enough?
Anyways, I highly recommend a 5450, it's an amazing card for light use, not to mention very affordable, my friend has his running a 1080p monitor without any problems.
Here's a link to where you can buy the card, you may be also to find it at a local .
electronic store like Fry's/Microcenter.
5450 on Newegg:http://www.newegg.com/Product/Product.aspx?Item=N82E16814141129
Also, since your mobo is old, I got you the 2.0 version, so you should have no problems with installation.