Going to restaurants isn't necessarily counter-productive to weight loss. I go out every weekend and I did during my weight loss too. As long as you make smart choices it's really only bad for your wallet
In New York the chain restaurants have to post their info and I find if they don't you can request it.
Smaller restaurants or ones that aren't chain places don't have to post their info, so what I usually do is find a similar meal from a restaurant that does post their nutritional information and sort of estimate it that way (you can find all of this online)
If I really can't find the information I'll usually make the best choice possible and get something that I generally know the calorie count of. I also don't eat the entire meal and take half or more of it home
Then again I just can't eat as much anymore! I don't really have to worry about portioning out my meal because I get full on small amounts.