The Small Matter of Keys
I touched on keyboard languages and layouts for smartphones back in June. Your Mac or Windows PC has the same ability, and having the right hardware is the key.
This is another one of those pointers aimed at avoiding frustrations, and getting you onto a good path right from the start. There are a couple of ways to turn when it comes to keyboards. Either will help, whether you're taking actual lessons on the computer, or just doing homework or taking notes.
Best way: acquire an actual Swedish keyboard -- sometimes labeled as "Swedish - Finnish" -- and make it your day-to-day keyboard. Your PC or Mac can change keyboard layouts very quickly, once you've added Swedish as an available language. (PC instructions here; Mac instructions here. Redhat here.)
The main payoff is easily finding the ö, ä, and å keys. I also just enjoy using the "real thing," and being familiar with any gadget before I have to be. If your typing skills are strong on the standard US layout, you'll be fine with the few differences while you're running the Swedish layout.
Amazon has a few choices. If you move fast, there are still two of these Silicon Graphics keyboards left. This model is very solid. I like it so much that I've bought two. This pic is a little better than Amazon's.
There's also a Lenovo model, which is little pricier but looks good. I see others with varying ratings, and some which aren't even USB! Buyer beware.
The other way: buy stickers to place over the keys of your existing keyboard. This is a less expensive way to go, by far. I would consider this for use with (cheap) external keyboards, but not for a laptop keyboard. Eventually the stickers are going to discolor, peel, or come loose. Search for "Swedish keyboard stickers" -- you'll find plenty of options.