It depends on what framework you are running you website. Not sure how far back 2012 will support .net versions. It might work if you managed it to work on 2010. But I would sugest you try to upgrade or build a new website, much more fun :)

I have an Episerver 4.6 solution, will this work if upgraded to a Visual 2012 solution?

thanks

You will have to try. if .net 2.0 i might work maybe. not sure you can make it run on your local machine though.