Drop this code into your page, after the closing </title> tag, and before the closing </head> tag:
Now remove the code from the <body> tag that specifies the location of the background image, in your case, it is this part of the line background="images/background.gif".
That's the backgound image no repeat taken care of, depending on your visitors browser of course, but it works on all modern browsers.
Regarding your tables, that's another story. There are a bunch of ways around this, and some are more desirable than others.
Try fixing the table width to 760 pixels and remove any height settings. Now fix the left table column that contains your navigation buttons to whatever is requires to space them out. While we're talking about your links, reducing the size of the images slightly would help a vast amount in controlling your table behaviour.
As long as your table is set to a fixed width and the left hand column is as well, any text in the right hand column should flow naturally, without distorting the table.
Note that there are more potential issues involved here than you could shake a stick at, so this may work forst time or you may have a fight on your hands. I notice that your table has several unused elements at the right hand side - if they aren't required, remove them.