Build an Online Store

We are looking for a professional and very very experienced, i really mean it - experienced Magento developer who knows in and out and knows the coding very well. (Should be able to fix any/most of the magento related issues/errors) Basic info : We have a latest Magento shopping cart but it's heavily customized (custom coded/ custom modules etc). Our current Gtmetrix score is : Page Speed score : C(74%) YSlow Score : E(59%) Page Load Time 11.2s (Important) So we need to optimize these scores. We are aiming to get a A or B grade and very important - we need to bring down the page load time to 1-2 seconds. Once again, our site is heavily customized, therefore we really need a experienced tech who could finish this task within our budget.