The router I recommend (Linksys WRT54G or WRT54GL) are both wired and wireless in one. If you don't need the wireless functionality then you can simply turn it off.
If you must use GPRS then I'd recommend one that connects via ethernet like the MultiTech MultiModem GPRS MTCBA-G-EN-F2 (850/1900 MHz GPRS Modem):http://www.multitech.com/PRODUCTS/Famil ... iModemGPRS
You would plug your router directly into the ethernet port on the MultiModem. Scott