Yes, definitely go for the coffee grounds. Sorry, but I can't recall the actual N content of the grounds. At our school/community garden it's a very acceptable alternative to manure (which we're not allowed to use for health department reasons).
We've been back to warmer days and the compost has thawed out again. I picked up a couple of buckets of coffee grounds and incorporated a bucketful into each of my heaps. Yes, I did remember to tear the filters into little strips. From my research, the grounds are tons more beneficial being put into the compost as opposed to being incorporated directly into the soil. The soil microbes love them. I also add a small quantity to my worm bin in the kitchen.
People ask if the coffee grounds are too acidic. Don't worry - the coffee drinker has already imbibed the acid and the grounds are just fine. (Which is a shame because around here we have alkaline soil and we'd love to have an easy source of acid.)