Side Scroller Help Desperately Needed!

Hi.
I’m making a side scroller game in flash mx 2004. my character is a movieclip containing movieclips of walking, standing and
jumping animations. I can make him walk left and right okay but when it comes to jumping i have this code:

onClipEvent (load) {
grav_y = 0;
jumping = false;
}
onClipEvent (enterFrame) {

if (Key.isDown(Key.SPACE) && !jumping) {
	grav_y = 15;
	jumping = true;
}
if (jumping == true) {
	grav_y -= 1;
	if (grav_y<=-7.5) {
		grav_y = -7.5;
	}
	this._y -= grav_y;
}
if (_root.ground.hitTest(this._x, this._y+45, true)) {
	grav_y = 0;
	jumping = false;
}

}

This works fine except that the character jumps while in the standing animation. where do i insert the gotoAndStop(“jump”); ??

Also i used the if(Key.isDown) function for when the character attacks but the animation only plays while the key is held down. how can i make it so he attacks when a key is tapped?

Thanx in advance