Existing website requires feature updates

We have a Freelancer style site ([login to view URL]) that is live but not adequately functional. There are a few improvements we require to be completed for us. The original custom script was created, there have been edits made, and are now at a stage where we require more edits. The script edits will potentially require PHP/MYSQL/JavaScript and probably some HTML/CSS experience. Change #1 Bidding on Projects: Current state: Currently a company can post a project and the project should be listed in a directory of projects. A Freelancer can view those projects in a list and then message the company/poster to start communications on completing the project. Currently the projects are created by a poster and then don't appear in the projects directory. Desired state: Fix #1: We need the projects to show up after posting. Fix #2: We need the Freelancers to be able to bid on a project with a price. Fix #3: We need the Poster to see bids on their profile from freelancers Fix #4: We need Freelancers to see bids they have placed on projects and be able to edit/delete their bid Fix #5 The Poster needs to be able to sort bids based on price low-high, rating of the freelancer. Change #2 Messaging Function Current state: The site has the ability to send messages and then open entire conversations only. Desired state: Fix #1: Have Posters and Freelancers able to send direct messages to each other and each side then be able to view and reply to those direct messages. Fix #2: Limit ability to direct messages from Posters to Freelancers if the Poster has an active project. Fix #3: Limit the ability to direct messages from Freelancers to Posters to when the Poster has an active project. Fix #4: Limit the ability to DM messages either way if there was a historically completed project between the 2 parties. Change #3 Searchability Current state: There is no ability to search through projects. Only the ability for visitors to browse the directory of projects. Desired state: Fix #1: Place a keyword search function at the top of the browse projects page that allows all projects to be searched. Fix #2: Rank search results by the number of keywords that match the search. Fix #3: retain the search results if a posting is viewed and the visitors goes back to the search result (so they don't need to re-search)