I need a specialist in Magento – web developer

The site on the Magento engine! Online store
There are various smaller tasks on the mile and the code in the tor it is hard to describe, they recorded on video !
And here's another problem !

1.Fix website speed, Google back all OK but the response is long on the server , we need to understand
2. Add a callback chat
3. To implement the function of discounts and promotions , type of promotion code for each customer 10 percent in the registration and just the option to enter a promo code which for example will come in the mail! Flexible system to make the shorter !
4.To make the data markup