If I were you, I'd not wait any longer to start serving notices and evicting them. Three months without rent is too long, but you probably already knew that.
If they do not pay, then yes, you need to go get a judgment against them in small claims court. In my opinion, getting that kind of judgment is easy, it's just a pain in the butt to service notices, summons, etc. Once you get the judgment, you still need to use the court to collect against them, and that is only if they have money to collect against. If they don't pay rent, I don't think your prospects of collecting are any good.
You could potentially sell the judgment for to a debtor collector, but I doubt you'll have a buyer.
So yeah, focus your efforts on eviction now. Cut your losses and move on to the next tenant.