How to add joining lines between points in an XYplot

I have some points plotted on an XY graph (see attached example on the left) and would like to add lines joining the points as shown on the example on the right.
Any suggestions how to do so? How can I fill the area?

In excel 2007 we have Radar graphs, is it possible to turn/rotate them? The example on the right is from a radar graph, but it is rotated 45 degrees, while the example on the left is from an XY plot.

Your help is greatly appreciated,
XcelGirl