unseen coolant leak and heater problems

I have had a coolant leak for quite some time. It is coming from the top of the motor somewhere and I do not have a pressure tester to check where it sould be coming from. Is this a common issue for this make and model? And this morning on my way to work I noticed that I had me heat on but it was only blowing cold air. It worked yesterday but now apparently it isn't. There was no fore warning of this just apparently stopped. What can I do to fix both of these issues? Thank you.