Advice on how to resurrect my 635

Some time a go, I took my '83 Euro 635 in for it's annual safety inspection. It failed for tires and the cat. As it would be, I got tied up in other things and before I knew it five years had passed. It is still sitting in the garage under a car cover and now I'd like to get it back on the road. I know I can't just dump new gas in it and expect it to run properly. Can anyone give me advice on an action plan of what I need to do short of delivering it to the local BMW repair shop and writing them a big check? A little more information. I didn't put Stabil in the tank (I didn't think it would be sitting that long) and it now needs a battery. No surpise there, I guess. Any advice is appreciated. Thanks.