using a 2wire 2701HG-D to share my desktops internet connection

I have an adsl modem / router that I would like to use to share my wireless connection. I am "Borrowing" internet from the neighbors but can only get a reliable connection when sitting in my dinning room window... I have connected an ethernet cable from my pc to my xbox 360 and am sharing the wireless connection with the lan connection in order to get on XBOX Live but the cord runs over the table, around the chair, and through my living room where my sons dog enjoys chewing on it, and my wife trips over it and NAGS!! I would like to use my 2Wire 2701HG-D ADSL modem / router as a wireless access point, but it does not have a WAN port... is there anyway around this issue (I know I could simply buy a wireless router with a WAN port but I cant afford one now as evidenced by the "borrowing" of the internet. besides this old thing ought to get some use out of it) any thoughts out there??