Joomla 1.5 fix for default/home page link on menu

I have a Joomla installation.

Everything was working fine but I tried to change the article the "Default" menu link was assigned to and now errors are occuring.

I have put a temporary redirect on the URL to try and reduce the effect but I need this done asap.

When "Home" is clicked, it takes me to an old article. Plus, I cannot assign any modules to the "Home Page".

When you type in my url, you will be takenn (through a url redirect) to the page that I need the "Home" page to be.

Currently, I cannot change anything on the "default" page.

Would need this done today. I'm not sure how long it will take, can you let me know predicted time. I'm hoping its a quick fix and down to my lack of knoweledge.