If nothing else works, try covering half the rad with cardboard and see if it makes any difference...some people are more sensitive to cold than others...or they drive with the windows open and wonder why it's so cold...(I do this, btw to keep the smoke out of my eyes)...
Plus, driving faster in cold weather makes it feel colder...wind chill is a factor there...I've had to pull off the highway a few times to warm up the Zuki...it's a convertible (no, the top was ON)...and the roof leaks...plus there is more glass area and that makes it even colder than other vehicles with less glass...
Wind chill is utterly irrelevant for a radiator (unless it's raining or foggy). They are dry.
Airspeed will make little difference if it's very cold out; once the underhood air is close to ambient, you're not going to make it any different by blowing it faster through the radiator.
Unless it's PAINFULLY cold out (at least subzero), a working RBV heater is completely adequate. These are very powerful heaters. If it's not warming up, several possibilities come to mind:
1. Blocked heater core or ductwork
2. Nonfunctional or mistuned temperature door
3. Low coolant and/or low coolant pressure (leaks)
4. Blown water jacket
5. Stuck-open or missing thermostat