Should I stay or should I go?

I'm going to try to be fairly vague, while giving all the relevant information.

I have the option to change jobs within my company, to a new location in city I'm not thrilled about living in.

I would gain marketable experience that would more easily carry over to other companies and allow possible future moves to other areas/states.

There would be $5000 of extra income involved, but also increased expenses (at least $1000 a month). I would have to put my child in daycare at least part time, as opposed to not having to currently.

Is being upside down and losing money on a 'promotion' worth the possible future benefits?

How do you measure opportunity costs vs. happiness costs vs. financial costs?

EDIT: Thanks for all the advice. I'm sorry my responses are all so rambling, but it's been nice to talk it through a bit. I will probably do some combination of requesting more money/other benefits, and seeing if I can be guaranteed to be there for a minimal amount of time (6 months, 1 yr?)