Please help with code

with reference to the Rin theme on my blog at
http://www.go2malawi.com/blog/

Some people cannot work out how to register on the site to make comments and I think its because the log in button is very small.

I have looked at the css and tried to be clever by adding the height thing from this:

#hmenu {
margin: 2px 5px 0 0;
text-transform:lowercase;
text-align: right;
float: right;
width: 440px;
}

to this:

#hmenu {
margin: 2px 5px 0 0;
text-transform:lowercase;
text-align: right;
float: right;
width: 440px;
height: 40px;
}

BUT NOTHING HAPPENED!!

Can anyone help with this?

Thanks in advance..