can't believe that you guys are struggling with this, lol, it's one of the first things my dad taught me when i got a car, checking and topping up fluid levels and checking tyre pressures and treads, etc
ok, Audi and VW use a longlife antifreeze called G12. it's pink in colour and shouldn't be mixed with conventional antifreeze because it goes a horrible brown colour. you might be able to get it from a local accessory shop, i got some from an independant just up the road from me. i got the neat stuff that you have to dilute 50/50 with water but you might be able to get it ready mxed.
in my experience you will, over a period of time, always see the level drop but it doesn't mean there's a leak, it's just a bit of evaporation. if i was having to top it up every other day i'd be worried but every 12 months would be normal.
*another public service announcement from ShineyDave inc*