Dry cleaning won't "fix it". All that does is swish it in chemicals and it often does shrink garments.
You may be able to have it steamed, stretched and blocked professionaly. Crepe wool reacts better to this process. A professional cleaner or tailor will be able to tell you if they take a look at it. No one here can give you a definitive answer. I would suggest finding one of those places that do both cleaning and tailoring rather than a chain cleaner.
I think its really the drying process that tends to shrink wool. You might try wetting it again and very carefully stuffing it with something or blocking it somehow so that when it dries it will dry to the right size. I.e. What bud said.
Unless it is already unwearable though, definately take it to someone who really knows clothing and especially wool. it would be awful to take a suit you can deal with and try to do something to it to make it better only to make it worse.
Pure wool always shrink, though it is difficult to find 100 % pure woolen suit now a days, i think companies are launching such mix material because of this reason.
