Hi,
If your completely new to web design it might be worth holding back from purchasing any software and do a little more reading around the topic as there are plenty of free alternatives out there, try coffeecup.
I think the best the to do would be to search around for a few templates and have an idea in general of what you would like to create.
Also, so, check out GIMP, it's a graphics software app that pretty decent and might come in handy for your web graphics, it's also free.