optimize magento web based

need profesional experience that can handle magento , my problem is my website was fine, nothing wrong.. but just the FACEBOOK like problem (( did not showing the right image on FB wall )) so i contact the developer where i bought the template,and they gave me the new replacement file under root - APP ( [login to view URL] and [login to view URL] ) so i replace it my self ... and now the result is the facebook like problem is solved but my website is become so slow in front end and back end .. and i also have change to best server magento hosting, but the result is same and i have try to optimize it and the result is better but..now have problems 1. under product page ( front end ) , i cannot see other page beside page 1 , so i cannot see page 2, i cannot change the layout view,etc -- it is stuck 2. sometimes still so slow on back end and front end , i never encountered this before i upload replace the new ( footer and head )) 3. my homepage there is 2 facebook like extension ((before, only one and i correct positions..)) i want to remove it,but cannot ,it will show error )) please see image attached and you will understand 4. if open my website using INTERNET EXPLORER ( ie ) the page is not well optimized , the image is overlay the product categorize, so i need to optimize it so it can be view by internet explorer ( ie ) as well like other browser ( safari,mozila,chrome ) and mobile based maybe i think this problem is all related to the file i replace ( head and footer )) and i still have the backup file ,before i replace it -- (( the old file is having error with facebook like issue )) before i decide who will be rewarded to this project i need detail email and communications first, just to make sure..that you are really know what are you doing and give me explanations ((( i have been working with others,but sometimes the result is different and to many excuse and not professional , so i need to make sure first ))