Hey Bluefairy, I'm sorry that I didn't reply quicker!!! If you are still watching this thread, the only place I know to really find the downloads is on my own forum. I hope nobody minds self promotion here... But the members of my forum asked me to create a download section so they have done all the work. They have found tons of different episodes, songs, clips, etc.
Here are How I Met Your Mother Downloads
sorry about putting my own site up, not trying to spam you guys by any means but that's the best source I know of for download stuff right now.