joomla expert

Hi, we need few modification to our joomla online store that uses virtuemart, the modification include 1. we need epay payment gateway to integrate 2. Need add 2 custom field to product page, that will be also included in checkout, payment and confirmation page 3. The checkout sometimes not clickable, need to be figure out why? 4. need content slider to integrate at home page, for this in admin when entering product there wil be check box , to show on home page or not thanks