I still can NOT figure this out!!

and it is really annoying me....
I love my Avi, but was hoping to take off the Valentine picture and put a new on in it's place...and I am not having any luck!
Could someone PLEASE PLEASE PLEASE help!
I would like to add this picture (below) to the start of my avi (in place of the Valentine's heart) but add some text to it...like Happy 5th Birthday Mojo or Mojo's 5th Birthday March 11th, or something like that.....but w/ keeping my other pictures the same and the avi size the same.
Can anyone help??!!
cupcake1.gif