I did not attend any language course, but after a few weeks I understood approximitely 70% of what people have been talking. For german speaking people I advise to read a swedish book (e.g. Henning Mankell) before your stay, moreover the audiopodcast from
www.sprichmalschwedisch.com, where you will find grammar lessons until level A3 and lots of vocabulary. Although most of the older (swedish) patients understood english, it was really existential at the hospital!