I have forced hot air and the unit outside has been frosted during most of the winter even on days that aren't so cold(50 degrees) the air coming out of the vents are cold and the temp inside will not get any warmer than 60 and the therm is set at 74... please help

Try this: set thermostat system selector to emergency mode, raise temperature a few degrees, and see if warm air is produced after a few minutes.

Supposing you are talking about a heatpump freezing up,, Its way past time you should stop using it and run on emergancy heat till you get the HP fixed,, can`t be good to keep running it,, all the harm it would cause running in emergancy heat all the time would be to your pocketbook,, but that's better than having to replace the heatpump