I've had success with Ceit's process, too, and I'd try that first. Try to get as much moisture out of your sweater as you can before blocking it. I use bath towels. Lay out the bath towel on a flat surface, place your sweater on top in a reasonable facsimile of its shape and roll up the towel with the sweater, like a jelly roll, starting from the bottom. When it's fully rolled, lean on it with your hands or roll the roll to get even more of the wetness out. Then, put your sweater on a flat surface where it can stay a day or two or so and smoosh it into shape with your hands. On the parts where it's badly misshapen, you want to do a heavy block, which is when you use the heel of your hand and your fingers to pull the fabric together, kind of like when you're shaping pizza dough if that makes any sense at all.
If this doesn't work, you could try washing it, drying it partially in the dryer (on low), and then blocking it as above. The dryer may help set the fibers. Be careful doing it this way, though, as it could also shrink. Good luck!
