Don't feel bad - people get scammed every day.

If you want to keep using LW 5, you'll need to get used to a lot of differences The User Guide & FAQ for LW 5 are here at the top of the page: User Guide - LimeWire

If you'd rather go back to LW 4 (more like what you're used to) then you can always download it... just click on the 'Get Basic' button & then use the link to download old installers on the right hand side - then you can download a 4.18.8 installer