Moses baskets are really nice for a little while, but they outgrow them quickly. I've got a lambskin ( http://www.ecowool.com/nursery-baby-and-kids/nursery-bedding/ecowool-sheepskin-baby-rug.html ) that I've put on top of a folded blanket next to the bed. That works nicely for longer!
One of my facebook friends just posted this contraption. I think it's super cool, but unfortunately over-priced. It's really just a pack and play with no legs, and a zipper opening. That zipper would be so handy though. You could crawl halfway in to nurse baby to sleep, then sneak out and zip it up! Or just sneak an arm through if babe just needed a little reassurance in the night.
I would just put a regular crib mattress on the floor next to yours. If your toddler is very rambunctious and you feel like you need to define the space a little better for baby, you could use a co-sleeper thing like this :http://www.amazon.com/The-First-Years-Secure-Sleeper/dp/B00012CHFI/ref=sr_1_1?s=baby-products&ie=UTF8&qid=1378138400&sr=1-1&keywords=cosleeper on top of the crib mattress until baby's bigger.