I need my WordPress theme to be customized!

I am intending on building a tutor matching website for my home country, much like http://www.wyzant.com/. Except, not as much complexity as their website!

I will be using a WordPress theme I have already bought called Business Finder: http://preview.ait-themes.com/businessfinder/wp1/home/home-with-image/
This theme is a directory where businesses can list their business. I'll need something similar, except NO MAPS.

Basically, a student who needs a tutor will use my site, and a tutor who needs students will also use my site. The site will need to have two separate logins and registration points (so two profiles); one for the tutor and one for student. The student will be able to search by postcode, radius to postcode, category and keywords.

After the student searches, they will be presented with relevant listings of tutors (much like businesses), and the student will be able to contact the tutor via a pop-up box on screen. The tutor will receive the message in their profiles (while a notification will be sent to their email) and will be told by our system if the student has payment information in their profile. I'll be using stripe as the payment processor where students can add their payment information (credit card), so I can manually debit AFTER the lesson has occurred. The tutor will log the lesson on the site (in their profiles) and will be emailed to me.

I have attached my concept to this job listing, and it's in the form of a flow chart. This design should not be too hard to complete. I am still yet to put together the actual format of the profile etc. but I know what the profiles will have in each of them.

Please, only serious web developers. Feel free to email any questions!