Redirect Site keep links?

I currently have a successful .com website which is a bit out dated now. I do however have fantastic links on this site and my natural google rankings are really good I am at the top of googles 1st page on most searches.

I have just designed a new website at a stand-alone .co.uk site which I was about to redirect my .com site to until someone told me not to as I may lose my fab links and rankings. Also I was told I should copy the new site to the .com address to keep the best rankings and links. Does anyone know is it better to re-direct or copy site across? If so how easy is this to do? Thanks in advance