Product attribute issues!

[backapparel]

I am working on my shopping cart and have experienced a major problem.

We have (2) T-shirt designs that come in Grey or White, Sizes S-XL are $15. Size XX Large is $17 and 3X Large is $18.

I can't figure out how to modify attributes and options to assign different prices to the same item.

I would like to have a drop down menu to choose the design--then the color---then the size.

Right now on my site I have each sizes listed as different item. check it out (www.backapparel.com) and go to (ordering and click shopping cart)
Any help would be appreciated

[Kristine]

Go to: Admin/catalog/product attributes
Insert product options for each: size color and design
Then assing values to each option, so you would choose size in the drop down box and then type in S then insert. Do this for each option and it's values. Now scroll down the page, choose your product from the dropdown box and assign options and values and price increase(+) or decrease(-) for that value. Easy as pie