Salesforce WebToLead Validation from PHP Webs

Requirements: 1) When a user submits a Shipping Quote request (using the sq ft calculator on any page like this: [login to view URL]), the website will check our SFDC instance to see if that user exists as an Account or Lead (if both last name and email match an existing record). a. If true, the website will simply send an email to "email address" that says "Existing client John Q Smith is requesting a shipping quote for Natural Strand Woven Flooring in the amount of 1,135 SQ FT, to zip code 11223. Please forward this email to his Lead Owner". b. If false, and the user does not match an existing SF account/lead, a new Lead will be created. 2) When a user submits a Samples Request, the website will check our SF instance to see if that user exists as an Account or Lead (if both last name and email match an existing record). a. If true, the website will simply send an email to that says "Existing client John Q Smith is requesting the following samples: Strand Woven Natural, Rustic Sienna Strand, and Classic Carbonized Horizontal . Please forward this email to his Lead Owner". b. If false, and the user does not match an existing SF account/lead, a new Lead will be created. Notes: 1) The website should treat either outcome as a successful request (a lightbox should always pop up saying “Thank you”… even if there is an existing client in the SFDC instance). 2) This cannot slow up the request process – it cannot make the samples request hang more than 1-2 seconds.