What changes do i need to make? any suggestions?? should i start a whole new concept on this wallpaper?

It's good.
But it is very simple.

Yay! halloween!
the texture is a bit distracting over the whole wallpaper, I would use it only in some places, or turn the opacity down so it's not as prominent.
I think you should try to find a different font.
I also don't think that white square in the middle really helps your wall. it's just sort of there... maybe making your charachter bigger, and going with a one color background and mixing up the pumpkins and bats?

How CUTE!!!!!!!

The scan is awfully cute, the font is sweet and well chosen, the background looks simple but nice... REALLY I like it...
But there is two things bothering me :
1) The texture you put on... Please remove it... I spoil the all wall...
2) The pattern of the pumpkin and the bat... I'm assuming this repetition is made in purpose... But I don't know... I feel like it's a bit too much for this wall. Note: the pumpkins look more like apples to me... :-s You should also try not to have pumpkins cut by the orange background.
Also, if you want to keep those bats... You need to move them a bit more... Or why not try to give to the bats a little move...

Note : the bats are pretty eye-catching... you probably will want to change the contrast on your scan to make it more obvious...

Ah, yes, halloween is coming up! anybody going trick or treating? even "old" people? lol =P

well, i have a personal dislike for textures applied through the texturizer filter of photoshop. so yeah...it's easy enough to guess that I don't like the texture you have there (and it's permanent for the layer too) try applying texture the usual way and see what becomes of it ^^

and the bats: the pairs on either side don't line up. those on the right are just a tad higher than those on the left. try to match their heights.

and the pumpkins (i lost my halloween spirit for a moment and thought they were apples o__O lol xD I'm slow today) i think instead of having so many, why not have a few larger jack-o-lanterns instead? that'd look neat.

and i dont see a sig ;D you need to make sure you have your sig on your wall.

so overall, that's about it. we'll see if I have more to say as your wall develops! good luck! =D

You pick the right theme since halloween is approaching soon. I'm a BIG fan of SO3 you know. But i'm ot going to make favorite just because of that reason. Oh,okay let's stop blabbering around:
1.) You know,your bg is simple. I suggest you use abother bg. Like night sky with a moon,a gothic castle and bats maybe will more make the sense of halloween. But if you don't want to,you can leave it like that.
2.) She's WAY too SMALL! Make her larger.
3.) It's good to texture your image,but if you take a good look at the wall,she's got textured too. And i'm not a fan of textured character. You may texture the bg but not the character.
4.) Your sig. Please..don't EVER forget this one. This maybe a small problem but it can cause rejection to your wall.
Okay..that's all i think. Nice job and keep working on that.