I'm almost 8 months post-op (I had gastric bypass) and I still have a hard time getting enough protein without a shake once a day. So you might have to just try to find shakes you like. This blog has some great shake recipes:
theworldaccordingtoeggface.
However, some good foods for the puree stage include:
fat free refried beans, with a little shredded cheese and salsa on top
ricotta cheese, nuked, with some marinar sauce and a little grated parmesan cheese on top (I still eat this, it's yummy)
Fage 2% yogurt (very high in protein- unfortunately I can't buy it where I live, but you should look for it)
and you can add unflavored protein powder to other foods. Don't add to much or you might get a grainy texture, but you can add a little to things like yogurt, mashed potatoes, cream of wheat, etc.
Kelly