Cool! I just ordered Fan yesterday and it is coming today from Ebay made by Behr for $324 Shipped. So to conclude what happend to me and the fixes are:

First my AC was working intermittently and AC is cooler when car is running, all of a sudden while I was in traffic, the expansion tank exploded( I could hear the pop) - I believe this issue is due to a bad condenser fan which is not moving air through the condenser when I am sitting in traffic in 100+ degrees.

Then I replaced almost every piece of cooling system except radiator and belts, then AC is working halfway, weather got cooler, I am driving around and AC is blowing very cold. However, AC is not as cold on passender side, which is still a mystery until I replace the condenser fan. (I ran the bmw 1.4 scanner and it tells me about the Fan Fault)

Today, I am replacing the condenser fan. Hopfully everything will be fixed!

Again, Thanks Upallnight for ongoing support and comments from other members!