The airbag light has come back on because there is a fault. Its all well and good clearing the fault, but if its still there the light will just pop back on.
That is also a high level of oil, my MK5 (and others Ive spoken to) hardly uses any oil and only rarely needs a top up.
Welcome along to the forum, as Wayne suggested, head over to the MK5 section and post up in there.