CSS musicians template rollover images

hi folks. can anyone help me figure out how to insert rollover images for the nav bar using dreamweaver.

i know how to click on the image, insert -> image object -> rollover image
fill in all the blanks. but when i finish it inserts the rollover image next to the original image instead as an actual rollover image.

i looked up on the web about .btnContinue and added that where they said but it doesn't seem to have an effect

(this is what i inserted
<style type="text/css">
.btnContinue {
width: 89px;
height: 27px;
display: block;
font-size 10px;
text-decoration: none;
background-repeat:no-repeat;
background-image:url(button.gif);
}

.btnContinue:hover {
background-image:url(button_hover.gif);
}
</style>
)

help. thanks
Ty