2000 Mitsubishi Diamante wipers, windshield & visibility problems

For several weeks it was becoming increasingly difficult for me to clear the windshield on my car and I attributed it to hot, humid weather. Coming back on the freeway one evening it suddenly became much worse and my husband and I tried many different combinations of cool/warm/fresh air to be able to see out of the window, but it never fully cleared. It was dangerous to drive under those conditions, but we made it home. There was a whitish film beginning to form on the window, visible in daylight.

I purchased the car used from a mitsubishi dealer, a month or so later I noticed a maple syrup type smell. The proceeding months the problem got worse and noticed that my windshield kept fogging up. I took it to my local repair guy who gave me an estimate of one thousand dollars to replace the heater core and informed me that if I dont I could have a computer failure because it is right under the heater core which in turn may cause an accident due to loss of control.