Z.S.
Hi M.,
The best sippy cups my son's used are the Avent ones. They're really durable and easy to drink from. If you've used their bottles, they can be easily converted to a sippy cup. (you just have to buy the different tops).
As for how many ounces of food for an 11 month old, I think they should be getting most of their nutrition from nursing (if you are, or bottle-feeding) but if you're feeding solids, I would say about 3-4 oz. per meal. Their tummies are still very small. You might want to ask your pediatrician. A good site to look up:
www.askdrsears.com