Complete Wordpress Website!

I recently installed a theme on my website using Wordpress. I need assistance in building pages & setting up invoicing through the website. I know of an existing site ([login to view URL]) that functions exactly like I want my site to function but I am having trouble figuring out how to get it there! My site will have the following pages (several of these are already set up but still need a little fine tuning) About, Blog, How To Bid, Shipping, Sizing, Contact Us, FAQ, as well as a landing page that I do not want listed in the header menu. The landing page needs to have a rotating image going across the top, just under the menu bar. I also want it to have a Facebook like box that shows my most recent Facebook posts and I want it to show a list of the visitors friends that have liked me on Facebook. I also want the landing page to have a section showing my recent blog posts from my website blog page (summary of most recent). I would like to be able to post on the "Blog" page and send a copy of the blog post to my Facebook wall as well. The most difficult part will be the customization of being able to invoice through my website...this may seem a little confusing to explain but I know what I want done is possible & may not be too difficult for someone with experience so I'm gonna try to explain this...I post items for sale on Facebook. Fans then comment to purchase/bid on the items. This is where the website comes in to play...I will invoice each customer/winner & I need to be able to do this from my website (so I may need to have a private page set up so I can upload images of my inventory & post them directly from the website to my Facebook wall when I am ready to offer each item for sale). I want to be able to assign the customer a username (which will be their email address) & I want to be able to assign them a password to sign in with so they can view their invoice, add customization/personalization details to their order, enter their shipping information, & remit payment via PayPal. In other words, I want the customer to receive an invoice via email. They will open that email and click the PayNow button which will link them to my website where they will log in & eventually checkout through PayPal but I do not want a storefront & I do not want the customer to have the ability to shop or do anything other than personalize their order (if they wish) & proceed to checkout. The only other thing they will be able to do is see lists of their paid & unpaid invoices & perhaps see the shipping status if possible. I would also like a log in button somewhere near the menu/header of the landing page. The other pages on my site really don't need a lot of work. I will finish uploading the texts that I want on those pages myself. I think I have covered everything! Please let me know if you are able to take on this project! Thanks so much!