Jo, just in case you can't read Japanese characters yet, here's another answer:

Sayaka-chan wa itsugoro kaette kuru no?

This one could be used by a guy or a girl (college age tops), but would sound goofy if adults use it. Or if Sayaka is an adult and you're not.

If Sayaka is an adult, use "san" instead of "chan". It's jut more respectful that way.

If you are an adult, try "kimasu ka" instead of "kuru no". If the person on the other end of the phone is quite a bit older than you, you might want to use "kimasu ka" no matter how old you are.

The choice of "chan" or "san" depends on Sayaka's age though.

Hope that helps,

Rachel Burney