How to Align Text on Navigation Bar

Hi you!
My idea to change css code like this, and your site look better

#topMenu{
	position:relative;
	float:left;
	left:50%;

}
ul.sf-menu{
	position:relative;
	float:right;
	right:50%;
}

#topMenu ul.sf-menu li{
	position:relative;
	float:left;
	left:50%;
}
#topMenu ul.sf-menu li:last-child{
	background:none;
}

https://i1085.photobucket.com/albums/j425/longdhb/YiiVN/Untitled.png

Thanks for responding, but I’m not sure what I am doing wrong. Here is a preview of what I end up with:

https://i103.photobucket.com/albums/m121/daniara85/code.jpg

All I did was replace the first 4 lines of code with this one in my style sheet in the topMenu section. Am I supposed to replace the whole topMenu section with just this?

Thanks for all your help!

Can anyone solve my dilemma? Please help! Thanks!