Bidding and Contracting Website for Private Business

I have small business for contracting and subcontracts. I receive contracts from requesters and find for them contractors and bring them back bids. I want to do this in an automated way. I want the requester to login/register and add his request to a predetermined list of services or jobs. The requester will set the time needed for the bid to be received. His request will come to me for approval then (if approved) will go to my listed contractors (by e-mail, sms and on their profile in the website). Contractor will review and submit his bid which will come back to me for [login to view URL] I approve, it will be listed against the request for the requester to see it. The requester will receive an e-mail and sms notifying him by the new bid. All info about the bidder (contractor) will be available to the requester but the requester info will be hidden from the bidder. The website should handle English and Arabic. It should be very secure. It should allow uploading officials quatations and attachments. There are few others cosmetics and workflows that can be discussed later.