Dealer should have given you a litre bottle for top-up purposes.
Only if you are on LongLife servicing, are they supposed to supply the top-up.
If you are unsure, I would call the dealer for clarification.
That is not good advice. Every single stealer (VW and Audi) in the UK (and France) has repeatedly tried to supply me with the wrong spec oil. I have regualar arguments with one stealer, who (a) does not understand the 3 different VW LongLife oil specs, (b) is unable to understand the difference between LongLife oil and LongLife servicing, (c) generally doesn't give a flying fcuk about the implications of using the wrong oil, and (d) admits to "occasional" engine failures due "incorrect lubrication".

The only definative way, is to read the owners handbook (and NOT the service book), take a note of the oil specs, and then look on the VW web site for their own authoritative list of appropriate VW approved oils.
The brands of oils I would personally recommend would be Castrol (or any from the same group, which include BP and Aral), Fuchs, Total, Motul. I would use Shell if you pushed me, and would rather have a wisdom tooth extracted than use Mobil.