short translation needed

I'd very much appreciate it, if somebody could translate a few Japanese sentences from this tune (from 1:57 onwards)
http://www.youtube.com/watch?v=g7WAe16y-oY

An approximate translation will suffice. Thank you in advance!

Who is doing that?

Who will go with us?

When are you leaving?

It is one thousand yen. (I don't get what exactly she is saying, but sounds like this.)

Many thanks! :-)

I've been listening to this tune for years and kept wondering ...

sen-en desu = It's one thousand yen
dare ga sore o shite imasu ka = Who is doing that/Who is wearing that?
itsu otachi ni narimasu ka = When are you leaving? (respectful expression)
dare ga watakushitachi to ikimasu ka = Who will go with us?
dai (yonju yonju yonju) yonjukka = Lesson 40

It sounds like someone simply liked the sounds of the language and used several random phrases - the tune sounds kinda cute, though :)

Thank you AK. Much appreciated!

It sounds like someone simply liked the sounds of the language and used several random phrases - the tune sounds kinda cute, though :)

Yes, the phrases sound beautiful. And although neither the music nor the composer (a little known American music producer) have nothing to do with Japan, I am "dreaming Japan", whenever l listen to it.

The song (along with some other interesting tunes from the same producer) are available for a free and legal download at http://www.epitonic.com/artists/som/ - if you are interested.