Well, then ask your local Mini dealer. They will do it for around $450 labor.
If you have a good mechanic that you trust, then have him read up on Randy Webb's website and follow his instructions. Any good mechanic can do this job, but a special pulley puller is needed to do so. If you get your pulley from Randy, he will lend you this puller.
If you don't find anyone in your area I can do the job, but you have to drive to southern Indiana, just across the river from Louisville. I do the Alta pulley for $150 if you furnish the parts.
Join our Mini Cooper Forums to talk about your new Mini. From reviews, mods, accessories, reliability concerns and more, this Mini Owners Club is full of info!