There is some professional software that already exists. I googled on
"hostel software" and these were on the first page. I chose them because
they both seem to have demo versions. Even if you have someone program a
database for you, it is good to have some standard to judge it by. Also, you
may find they have some functionality that would be nice, other than just for
tracking your clients.

http://www.hotel-software.com/

http://www.dustysoftware.co.nz/