I need an online database for an agency

I need an online database to store staff records. I need to be able to filter through and find find staff by various different specifications. If possible I would like staff to be able to log in and change availability etc.

This may push it to far but if I could get something where by staff were able to submit invoices online and have an automated email to say it's been received and then a button I can press once it has been paid to let them know and mark it off as paid on the system that would be great too

I don't know any thing about this stuff so my price is just and estimate

One thing is I wold like the interface to look nice and sleek not just unfinished and naked

This is for an agency that hire dance teachers on a long and short term basis so having all this information in one place is really what I need