I am looking for a php developer to create a ratings system on my currently existing website.

I am looking for a php developer to create a ratings system on my currently existing website. The ratings system (not too dissimilar to the ratings system on PHP) will rate teachers based on 5 criteria and then give an overall score.

I am developing a website for teachers and students in Japan. The website allows teachers to add their teaching profile to the website. The teachers profile information is stored in a table in a DB.
Students can then view a separate site which displays all of the teacher information. If the student wants a lesson with the teacher, the student contacts the teacher directly.
I wish to add a function to this, which allows students, who have had lessons with teachers (or have tried to contact them via email) the opportunity to rate the teacher, based on a number of criteria and/or leave a comment about that teacher.
The ratings for the individual criteria as well as the overall average, are stored in a table and can be then attached to an area of the teachers profile.

Potential Difficulties
Part of the site is currently being developed by another developer. Although it expected he will finish soon, there will likely be a period of overlap between him finishing and the other work starting. Some of the tables he will be using will also be required to develop the ratings element of the site. I understand this has the potential to cause some difficulties, however I will be communicating at all times with both developers to try to minimise any potential conflict.

Graphics, Images and Text
I will provide all graphics and text. I also have created in XL, screenshots of how the pages will look and what the functionality is. I will email this to interested bidders.