80q coolant flush/refill worry

[Megan Bigelow]

So I decided to flush and fill the coolant tonight on the ole 80q. I 
drained/flushed it without incident, and then here's where I went 
wrong. The bentley and the Audi coolant bottle called for a 50/50 mix, 
and bentley said the cooling system's capacity for that was 3.5L of 
each water and coolant. Not realizing that there is still water from 
the flush stuck in parts of the system, I measured out 3.5L of water, 
added it, and then tried to (unsucccessfully) add the approx. 3.5L of 
unmixed coolant that was in the new bottle of Audi coolant.

Oops. There was 1.5L of straight coolant still left in the bottle. 
D'oh! And, upon letting the car idle until the fan kicks on, the 
coolant light flashes, and it's definitely not low. So I think it is 
overheating.

I guess this is more of an "I'm stupid" post than a question, but I 
just wanted to run it by the list's collective knowledge that what I 
need to do is drain and refill properly before draining and flushing 
the whole system again and buying more coolant at the dealership 
tomorrow.

Curses,

Megan