A/C & Acceleration.
 

Hello!
I bought my mini a few months back. It's a 2002 so I knew I'd have a bit of work to do. I have a 5 speed manual transmission.

My a/c doesn't work. It occasionally blows cold air but does not in the summer at all! The heater works great however. If I am driving with the air on say on the freeway or a busy street, if I slow down and the air is on I can't always accelerate except a few miles per hour over what I'm going. Obviously this a fun thing to do, and it's not quite safe to have to turn of the air and wait a second or two before being able to accelerate over 4 miles an hour faster than the speed I've slowed down too.

I was wondering if anyone else has this problem? What could it possibly be? I've replaced both the air and cabin air filters. Is there a leak somewhere? Could a simple charge fix this? I'm new to mini and I've never heard of this happening before.
Thanks for the help!