I've heard people mention paintscratch.com before as a resource for touch-up paint. I ordered a little touch-up pen from them and it seemed to match pretty well. I have no experience with sprays, however. Might be kind of expensive for you to order from though since they are here in the US.
My car (91 E30 318is) is Alpine II, so I would guess yours would be too, although it might be different, being a Euro model. There should be a sticker under the hood that says something like "BMW-Alpinewieß II" that would confirm it.