The belt runs off the crankshaft, and turns the camshaft, which turns the distributor. Camshaft also opens and closes your valves.
Crankshaft turns by the starter.
Crank turns, distributor doesn't, belt is broke.
Easy to replace, belts are cheap, but you have to turn your crankshaft and camshaft to the right position before installing the belt, or your engine will never run right (if at all). Timing is everything, (not electrical timing--turning the distributor--this is mechanical timing).
I don't know where you are, but in general the belt will cost around $30, and labor maybe $150.
If you are good with tools, and patient, you can buy the book for $25, and the belt, and do it yourself. In the store, you can usually read the book a bit, and decide then if you want to do it yourself or not. Usually not hard, but you must do it EXACTLY as the book says. You will get really greasy, and it will take you 3 times as long as the mechanic--but great experience.
Some extra tools may be neccesary (read the book), to find "Top Dead Center" (TDC). Hopefully not; on a Subaru they may have marks on the pulleys, to line everything up just right before installing the belt.
Hope this helps!
As far as I have been able to find, the engine in your car is a non-interference type (as has already been stated above) and I found the belt you need (one for each side) for about $18 each ($36 total) at Autozone.
But don't run out and buy them just yet. You seem to have said above that you have the Haynes manual (they are better than Chilton IMHO), so review the timing belt procedure thoroughly, then take the book to your car, open the hood, and see if you can identify the what the book suggests you do.
As it stands now, if you want a garage to fix it, you'll have to have it towed to the garage. If you start fixing it yourself and muck it up, you'll STILL have to have it towed and pay someone to fix it.
I'd give it a go. Then again, I'm elbow deep on the same project right now, in my driveway, with a Haynes manual, on a 96 Dodge Intrepid. (How's it going? you ask. Buy Ford.)
I have replaced the timing belts on my '86 Subaru, and the marks are there, you just have to follow the instructions in the Hayes book very carefully. Since this is a boxer engine, there are two belts. The book will tell you that you need several special Subaru tools, but I was able to improvise; just figure out what the tool is supposed to do, and you can improvise as well. All that is really needed is to turn the pulley to generate slack in the belt so the tensioning spring will adjust properly.
Hope this helps.