Magento Checkout Fix + Paymentoptions + Cart -- 2

Hi , I need one Expert in Magento who can Fix the Checkout. Its a Gomage Lightcheckout. IMPORTANT THE EDITS MUST BE NOTICED AND THE ORGINAL FILES MUST BE RENAMED IN : [login to view URL] TODO -Addtocart fix at mainpage (adding works not at home) redirects to checkout instead cart. -adding two paymentoptions sofortkauf and vorkasse. -checout process very slow loads hangs sometimes ajax bug ? The whole Order Process should work. greetings german speaking preferred or PPL with a Company or Portfolio Page