Watch the Day 13 online guitar lesson by Ravi from Learn Guitar in 21 Days
You have five chords down now, but let's not be focused on songs using five chords! Instead, try some new ones from the list that you haven't attempted yet, choose ones using two, three, and maybe even four chords if you feel adventurous.
You should be able to find quite a few using various combinations of the chords you know. If you feel like you are not familiar enough with a particular song, try searching for it online and listening to a clip (Amazon is a great resource for that) that will jog your memory!