Napa also sells combination U Joints. You might have more luck finding them locally over the weekend. Here's a link, you just need to know which dimensions you're after:
http://www.napaonline.com/Search/Res...word&Nty=1&N=0
Sorry the link didn't work. Just go to Napaonline
http://www.napaonline.com/ and type in "combination u joint". When it asks is this for a specific vehicle answer "no". It will show you the part numbers of the various offerings with the dimensions of the yokes and the caps. If it turns out to be a 1310/1350 combination, the part number is
PUJ 348.