I have gray eclamation points next to my songs on iTunes?

I downloaded music from Limewire a long time ago and recently got internet back on my laptop and found out about the whole court order thing that went down so I decided to experiment with some other sites. I personally liked frostwire but after a few days of use it couldn't get connected to my internet and it needed the password to my internet to get connected and so I decided since I couldn't use frostwire anymore I should uninstall it so I did. By mistake I didn't save the music to another folder besides frostwire and when I went to itunes all of the music I downloaded before couldn't be found and had gray exclamation points to the left of them. I didn't know if they could still be uploaded to my iPod or not? Also I experimented with a few other sites like bearshare and iMesh.. stuff like that but the majority of their songs are formatted as WMA and can't be converted so if you know of any other sites that you particularly favor or are like frostwire or limewire I would gladly accept them? :p All answers to these few questions are gladly appreciated, please and thank you. :)