to get the album artwork, go to iTunes and go where you have your music saved in a playlist. highlight all the music (crtl-a) then right click on the music and go to "get album artwork". you need to be logged into the iTunes store to do this and only the songs with the correct title, band name, and album name will get album artwork.
now to get lyrics, its a much longer process. you have to do each song individually. first, right click on the song you want lyrics for, go to "more info" (i think its the first one), this screen will pop up and at the top there is a label that says "lyrics". go to a website and copy the lyrics of that song and paste them into the text box you get when you click on "lyrics". this takes forever especially if you have as many songs as i do (702) so i suggest doing one band a day (today ill get Avenged Sevenfold lyrics and tomorrow ill get All That Remains lyrics, etc.) or something like that cuz it can get really annoying and time consuming, but its not always worth it. oh, and dont forget to click "ok" or "apply" when your done. i forget what it says. this is how to get them on a PC, im not sure if its the same way on a Mac or if you use command click instead of right click