"W" in German is pronounced like an English "v" and a "v" in German is pronounced like an English "f". http://www.learnalanguage.com/learn-german/german-culture/?ModPagespeed=noscript
Nope, I can't stop singing the darn thing :D
Actually, I just looked it up and learned a LOT more German (and French)!
Willkommen, bienvenue, welcome
Fremde, etranger, stranger
Gluklich zu sehen, je suis enchante,
Happy to see you, bleibe, reste, stay
Willkomen, bienvenue, welcome,
Im Cabaret, au Cabaret, to Cabaret
As much as I'm familiar with the topic (not that much even though I studied German in elementary), I'd say that 'Willkommen' is translated as "Welcome" but in context that you invite somebody to your home and etc, but "Gerngeschehn" you'd say in context where you did something for the person so it will translate as "You are welcome" or "My pleasure" or "Don't metion it"
Because you're welcome is translated as "gern geschehen", and you use it when you want to say something in the context of "my pleasure", "don't mention it", in other words mostly when you did something for the person.. but "willkomen" translates to only "welcome" since it's like you're inviting the person in the house