You can apply for China Tourist Visa(https://www.travelchinaguide.com/embassy/visa/tourist.htm) to visit your girlfriend, the invitation letter from her, photocopy of her passport information pages and the Chinese residence permit on her passport are required. You need to prepare your passport, one passport photo, one filled visa application form, round-trip flight tickets.

Thanks for a very prompt reply...yes my Visa is still valid until May 2011.