Smoke/Fluid from air vents

I have a 99 Jeep Grand Cherokee V8
(purchased it recently) and noticed that
when I turn on the heater, a cloud of smoke
emits from the air vents. It forms an oily
most on the windshield which smells sort of
sweet and Smokey. I haven't attempted to try
the a/c believing I would be looking at the
same situation. I also seem to be using an
abnormal amount of coolant. I have had to
refill the overflow bottle twice within two
months and have been noticing a burnt
coolant smell. I'm sure this problem is
beyond my ability to repair, but if anyone
could give some insight of what is be
looking to repair, at least I'd be able to come
up with the money to have it professionally
done. Thank You