Please see below.
I have tried but can’t figure out how to improve it. I’m working in Joomla 1.5
Do you have caching turned on in your Joomla settings? What you are seeing is likely the result of a slow database interacting poorly with Joomla’s desire to make a bazillion database queries to generate the page. A page cache can help hide that but the only way to really make it faster is to talk to your hosting provider and see if it is expected (on cheap shared hosting plans it is very common for example).