[WTB]Shopping Cart (Needs to be Simple and Easy to edit)

First post and here it goes!

I am currently in charge of running a restaurant's website for it's to go section, however they need online check out and shopping cart. I have tired xcart but editing all of the templates and CSS files isn't what you can call having a good time. Here is what I need:

-Being able to add items in and out(both in shopping cart and backend), change the prices, quantities, and integrate it into the site without much hassle.
-Total Cart
-Ability to accept paypal, debit, credit card orders.
-Security

I have just about enough php knowledge to do some editing, however I am not a experienced php user. The website is done, just need to add in a shopping cart and should be ready to go.

Here is the website:
http://www.weekdaycheftogo.com/preview

I will not reveal my budget for various reasons. =D However if you are able to do this, then post your cost/fee's and I will get back to you. Also if you have a working version of a shopping cart then that would be great as well.

***EDIT***r
I posted this in the wrong area, A admin can remove the post when ever they see this. I will make the post in the correct area