Geno8r:
Mate do yourself a favour and go to a proper exhaust shop and get this done the correct way. I had the exact same problem (only my snapped bolt was the firewall end) and only had it fixed about 1mth ago. The problem happened 8mths ago (or... about 10,000km ago) and my car was running like absolute sh1t for the past 5,000km. Boost was erradic, exhaust noise was loud and droning, throttle response was terrible, power was down a good 40rwkw. Go and get this problem fixed ASAP instead of waiting 7,000km until your major service (it will cost more then).
Don't just fix the problem that you can "see" because the problems you can't see are:
More than 1 bolt will be snapped - gauranteed
If you are replacing 1 bolt you may as well replace them all.
Your manifold may have warped (mine did which required extra labour/expertise)
IC pipes and Turbo need to be removed
Radiator fluid needs to be changed
You need atleast 1 gasket.
It cost me $581 to get my car fixed at a local "muffler man" and took 1 guy about 7-8hrs.