Zen-cart Custom programming

I am currently running zen-cart v1.3.9c and are looking for somebody to make the following custom programming changes: 1. Lock adding items from only one category.. ie, as soon as i add an item from one category, only allow items from within that same category to be added to the shopping cart until items are paid for. 2. Setup attributes to categories (ie zip code) . Or show me how this can be done. I want to find categories by certain attributes. 3. Create pre-defined searches so it finds the categories per attributes above... ie: a checkmark performs a search to find categories that match the zip code you type in a search box (show me categories near me by zip code) 4. make it so orders above $5.00 get a $1.00 fee added to them (opposiste of a 'minimum order fee') 5. make category name print on receipt and packing slip once you get the job, i'm sure things will get more sense.. i will give more info to you. thanks for bidding!