Wordpress Expert

I am starting an online business selling gadgets within Philippines. I already built my website using wordpress with the help of free plugins. I built it so I can add the details according to what I prefer which is usually difficult if I let someone do it for me.
I haven't made the website online.
Now I need someone to finish the payment processing. I like the "wp simple shopping cart" plugin format but this plugin lacks other functions I need.
I have a products page and shortcodes are added to it to add the items to cart. I want it to calculate shipping fee for Metro Manila and province. Then there is option for paypal, credit card or Bank deposit. Then confirmation email is sent to customers so they can pay thru paypal or bank deposit.
Most importantly, I should understand what has been done so I can personally make revisions in the future.