Okay, after looking at some pictures of R2D2, it looks like that front, 3rd foot pretty much looks like the ones on the side, sooo...............I can duplicate one of the existing feet, edit out the parts I don't need and make a 3rd foot. HOWEVER, I may not be able to create the piece that attaches the 3rd foot to the underside since it would require me to actually model that part and I can't seem to find any decent images to work off of so whoever builds this will just have to get creative and by looking at images, just try to make something to put in that place to attach the foot. :\
EDIT:
Ummm...........wow! This is gonna sound funny, but there WAS an EXTRA foot INSIDE of R2D2! XD When I opened up the model in Blender and duplicated one of the other feet to make a 3rd, I noticed some odd lines inside of the main body. When I looked at it closer, it was the 3rd foot! LOL So, all that work I just did for nothing. :\ I will pull the foot out of the body and unfold it. XD