Limewire? WTF were you thinking. Your laptop probably won't download iTunes because it's been critically damaged by malware that infected your PC after your LW installation rendered it vulnerable to cyber-attack.
Limewire is a horrible program, but for your purposes, the immediate thing to realize is that it's no replacement for iTunes, and if your computer won't allow you to download one of the most widely downloaded media apps in the world, then you've got bigger problems with your PC than simply not getting music to your iPod.
You need to specify why your iPod won't download iTunes - what happens. If you can explain why you can;t do it, at least describe what happens when you try.
Then get rid of limewire. Because it sucks. There are better alternatives out there, and unlike them, LW has a horrible rep for compromising the security of your computer.
If you must steal music using peer-share software, AVOID LIMEWIRE AT ALL COSTS. Consider getting either eMule or WinMX – I’ve used them for years happily getting all but the most obscure stuff. WinMX may have a high learning curve, and you need to make sure that you’re getting a version of eMule from a trustworthy site (don’t just pick the first site that shows up when you google – that’s a boneheaded LW way to get stuff, and you need to get past that).
You can also download from internet sites like beemp3.com or mp3raid – though don’t hesitate to ask around about how safe such sites are. There are no really safe sites – any time you’re downloading, you’re risking an infection.
You can also get music from YouTube. You can download using programs like youtube downloader (again, make sure you get that from a reputable site). Some of these programs will convert the flash to mp3 – if they don’t, a simple program, like Quick Media Converter will simply do the job.
You can also record streaming audio using programs like Audacity. Audacity will save the stream as an mp3. (Audacity is also handy for making your own ringtones). Besides youtube, you can stream from sites like LastFM or the websites for FM radio stations.
Lastly, you can easily rip music from CD’s you borrow from the library or people you know.
But under no circumstance should you keep LW on your computer. Besides malware, LW just isn’t that good. Many users are selfish leeches who don’t share their own music. The network is full of fake files – winmx had this same problem but managed to get past it and is now much more reliable despite being less popular (or maybe because it’s not as popular).