Things to try

I am not quite as tall as you, but at 6'1 I still have a few issues.

Like has already been suggested, put in a smaller steering wheel, mine is 330mm diameter.

The other thing I discovered is that even with the seat belt mechanism behind the seat there was still a bit of room. In about 10 seconds with an angle grinder you can cut another notch in the seat rail. This made the biggest difference for me.

Another thing to check, is the floor the right shape? Mine had been pushed in a bit, fixing that helped too.

I have been driving the car like this for quite a while now, but I still need a bit more room.

I will be fitting one of these soon:
http://www.racing-seats-usa.com/853l2.html