You need to do diagnostics and not just throw parts at the car. This is a bad habit to develop and just wastes money and time. Go back to the first thread you created and follow the directions posted there. There are tools to diagnose blown head gaskets, and easy ways to test thermostats. Use them.

 

Is it overheating because the water/coolant is LEAKING out? If so, that is your real problem. Try to figure out how/why the water is escaping.
If so, then:
Your car is overheating because it has no/low water/coolant.
Your heater is not working, because there is no water.

For temporary use: Fill the water every day. Fill the water/coolant two or three times a day, if needed.
Put water in it before you leave in the morning. Put water it in again, when you get to work, or to the store.
If you fill it with water every time it gets low, your car will work and will not overheat. For temporary use.

If you fill it with water, the car will not overheat for 30 minutes or 2 hours and the heater will work for 30 minutes or 2 hours.
Until enough of the water leaks out. (Or however long it takes)

I did that for a few weeks, until I figured it out, and had to replace the head gasket.

But you have to figure out where/why the water is escaping.

 

could be water pump, do you use tap water or coolant ? be honest

 

These 7th Generation civics are very well known for blown head gasket. It happen to me on my 2001 civic and sometime heat would be ok but on stop light it will completely go away finally I had to do the head gasket to fix the problem. Are you hearing a liquid gush when you put it in drive and move in first gear? If it does that means you have air in your coolant system and that normally is due the head gasket leak. Hope this help.