Filtering a portal with Availability

[csharpmin]

I'm working on a database for my babysitting business. Right now, I'm trying to create a portal in the Jobs page that shows what sitters are available for the given job time and date. I have successfully created a portal that shows available sitters but it uses a script to work. I'd like the portal to automatically populate availible sitters for the selected job using time and date criteria. Can anyone help? I've included the work-in-progress database. It has little formatting, and I have yet to include some of the more basic fields needed for full functionality. (Client addresses, etc.) Thanks in advance for any help or pointers.

Sitters_5.zip