With the latest iTunes, if the sidebar (along left side of window) is hidden, from the iTunes menu bar, under View, select Show Sidebar.
In the sidebar, the iPod should appear under DEVICES. Does it appear there?
If it does, the iPod is recognized. Select it there. The is a row of buttons near the top of the window, starting with Summary. Click on Music next to Summary. This is the iPod's Music screen, where you tell iTunes how to sync songs to your iPod, if you are using automatic syncing to load the iPod. Make sure your two new purchases are included in your selection on the Music screen. If you are using the manual method to load the iPod, do not set up the Music screen; just drag the new songs to the iPod in iTunes.
If the iPod does not appear in the sidebar, please post back.