Hey there,
You invited me to your project and this looks interesting, so I thought I should place a bid!
I've extensive experience with the whole LAMP-stack (and more specifically PHP) so I should fit right in :)
I have a couple of questions first, though:
* When you write "check/add payment system", do you mean that we should integrate visa/mastercard-transactions on the site?
All card-companies that I know of have incredibly tough requirements before they allow you to handle transactions yourself. I recommend PayPal or similar solutions instead!
* When you write "integrate illustration", do you mean that I should document the current system in place? If not, please elaborate!
Also, I prefer to work per hour, and I bill per day (e.g. an invoice per ~8 hours).