Because the network's constantly changing as users log on & off (so files available change also), make sure to search at different times of day/night.
Varying your search terms & using different categories (eg Audio, All Types) can make a difference to the results that you see

You can also click on LW's Connections tab (if you don't see a connections tab, go view > show/hide > tick 'connections'). Now right click on one of the hosts there > remove. Now a new host will take the place of the old one. Changing the hosts that you're connected to (you can change them all) can make a difference to the results that you see.

As for your download speeds...are speeds always slow? You can do a speed test here & tell us the results.
Speedtest.net - The Global Broadband Speed Test

Who is your ISP?

Download a file from here & see what kind of download speed you get.
Magnetmix

Also check out this thread (the first few posts by murasame) for tips about configuring LW.
A few things to consider while configuring Limewire for optimal performance...