Is there an English speaking employee?
Eigo o hanaseru hito irasshaimasu ka ?

I'd like to change this into yen.  
Kore o en ni kaete kuremasen ka?

I'd like to change yen into U.S. dollars.
En o bei doru ni kaete kuremasen ka?

What is today's exchange rate?
kyoo no kookan reeto wa ikura desu ka?

Can I cash traveler's checks?
Toraberaazu chekku o genkin ni shite kuremasen ka?

I would like to buy some Japanese yen.
En ga kaitai desu.

My ATM card is stuck in the machine.
(Cash) Card ga kikai-ni tsumari mashita