Bicycle Tutor

I posted on here a few days ago about problems shifting my new bike. Now after doing some riding I've come to the conclusion that my handlebars need to come up a little. I looked in the manual and all that did was confuse me. So i tried taking out the bolt i thought would allow me to rasie and lower the stem. After i removed it the bars didn't move. I am wondering if they are even adjustable at all. I looks like i can tilt them back more but there is a sticker on it saying not to adjust them.
For a reference of what I'm talking about here's a link ta a pic of my bike.
http://walmart.scene7.com/walmart/flash_...http://walmart.scene7.com/walmart/flash_zoom.jsp?company=WalMart&sku=5585808&config=WalMart/zoom_config&default=0003867559788&title=700c%20Men%27s%20Schwinn%20Pathway%20Comfort%20Bike&categ
Any ideas?

Well it looks like an adjustable stem.
I assume that you undid the bolt that is surrounded by the yellow sticker?

Sorry for the slow response, yes i did loosen that bolt but the one on the other side won't budge. I've almost stripped the darn thing try to get it loose. Any ideas?