Honestly you should scrap that one bro because of the colors go do a clipping mask tutorial and then a Regular sig tutorial using c4d's on youtube that'll clear up some issues i think.
if you have any questions im always here to answer im fairly new at sigs too so i dont know everything but i am able to help some
as far as clipping mask tutorials-- this is a nice video for that YouTube - Clipping Mask Tutorial and theres also a tutorial for it in the 1st site i gave you
youtubes a pretty good place to find tutorials too just type in what youre lookin for theres usually some good vids that can help you out
and one of the design team members has a tutorial section in his forum -- http://www.xiledgaming.com/forum/showthread.php?t=101993
alot of the members do have tutorials i believe in their forums if you go to the design team member section and just click on any of the members just search around im sure youll find some
also if you use regular pics and what not then you can easily play with your blending and if you keep everything seperate from the picture you can easily clean up your images with your background eraser tool