Raising ambient temps in a tack WITHOUT heating entire room!

I purchased a CB70 rack from reptile basics about a week ago. In emails from the company, I was told that in a room temp of 70-73, I should see ambient temps of about 78. I fine tuned my hotspot, and carefully monitored over the next couple days. We were having a warm week, and my room was at about 75. Guess what my ambient temp was? 75!
Apart from heating my whole room, is there any other way that my ambient temps could be boosted?

Thanks, Benek

Rrrrg *Rack*

There are not many options, tubs/racks biggest shortfall is that the air temp in the tubs is completely determined by the air temperature in the room that they are in.

There are some heaters that will only heat part of a room, but pretty much no matter what you are going to use something external to the rack.