Alternator defective Audi 80 Cabrio NG

Hello guys! I have a problem again! I used the search but somehow I can’t find anything that fits my case exactly! Can a short diagnosis make before I drive into the workshop and get fucked up!? Car: Audi 80 Cabrio NG 2.3l Year of construction 1992 Yesterday evening started, without any problems! Interior lighting a little dark, then when driving after a few meters instruments in the combo failed and engine went out while domes. Stopped, tried to start, n ichts, no starter, a bit of lighting, ZV and FH work but (window but very slow)! Battery older than 1 year, I don’t know exactly! If one knows exactly what it is, much more cost estimate or alternative!? Thank you