Merge Test DB into New Install

Hi,
I am very new to sql and MyPhp. I created a site on my account and want to move it to a different DB. I exported the sql testdb and imported it into newdb but it repeated the line items with a diff prefix.
I want to import so that I merge kxo_posts into eli_posts, etc.
Can someone tell me how to do this? I tried diff ways explained here but none of them worked so I am doing something wrong.. Thanks
Kate