Coolant Frozen

[Tsi]

Alright here's the deal, I believe my coolant is frozen. I can't remember what kind of mix I put in the car, it was during the summer soo I'm sure it was more water than coolant. The reason I think its frozen is because when I start it up the engine revs high and keeps climbing slowly. The block is a built 6 bolt and I don't want to ruin anything soo I shut the car off after a few seconds. Could anybody help me on what I should do, just let it run until it finaly unthaws? Any help would be appreciated.