how do i fix my heating problem?

Usually I would answer that by talking about heater core, but you describe something different. There is a device that will move where the blower puts out, does it go to defrost on the windshield Ok and get warm? Can you set it to your feet ok? If not, the trouble lies there, I will have to research that system to see if it is vacuum operated or what.

it defrosts good but when i set it to my feet its still cold air flowing

Because of the position that the core is in (horizontal flow entering at the passenger side), if air becomes trapped in it, the result will be one side of the core will heat up fully and the other will not since there is air displacing the hot coolant. Of course when this occurs, the air sent across it is diverted in the duct work and you end up with one side of the car getting hot air and the other side cold to lukewarm air. Or an obstruction of the duct work, like a piece of paper got in there ..now, the fix. Make sure your radiator is topped off, if not put some in, full to the cap. Cold. Do not pop a hot cap Run car. with heat on full blast. Let cool, top off again

i already topped with coolant but it sill has mostly cool or lukewarm air on 1 side and straight cool air on the other

Sounds like it need to be bled of air, Use the heater a lot and keep an eye on that radiator, usually it will bleed without an elaborate fix

Thirteen year old car... I would check out the vacuum hoses - I would guess you have a leak and the doors aren't moving all the way.

Question. I have a 2000 Eclipse and I had to have the radiator replaced a couple of months ago. It's getting cold now and I have noticed the heat isn't hot. If the mechanic say, forgot to "burp" the radiator, wouldn't 2 months be enough time for any left over air bubbles to work themselves out?

my hoses are preasurized and hard i dont know whats happening temp rises and drops randomly any help plz