I bought a "pet gear" puppy play pen online - off ebay, from KC Kayla's pet supplies - I'm sure i could find the link for you. It's very good quality - and it's pink!
I take my pupp to work and it stays here, but it is easily portable, and just the right size for a food/water area - 1/2 a pee pad and play room. She goes on the pee pad in there 90% of the time for #1's, and maybe 50% for #2's. What I've been doing is - when she wakes up from her nap I put her leash on her and direct her to the pad, when she goes on it I praise her.
She hates the play pen though - really, she does. but it is necessary