Buttons need to be on top. They are an "interactive" layer above the page. So to accomplish what you want, first make your text frame. Then select it with the Buttons panel open and click Normal appearance to make the text frame into a button. Give the interactivity you want. Add other appearances.
When you export (File > Export > Adobe PDF (Interactive) and view in Reader or Acrobat, you'll see the "pointing finger" indicating a link.
Click on it and you're at your website (in this sample, www.adobe.com)
Don't use Apple Preview for proofing. It's got many failings, especially when working with forms or interactivity (not to mention using it to proof anything for commerial printing. Use Reader or Acrobat.
I get it to work by grouping the text and background before making it a button.
Cheers Steve, Appreciate you taking a few minutes to explain! Very helpful
BTW I meant the Preview panel within inDesign not Apple's Preview, im not that bad
Good, I'm glad you meant the Preview panel. By the way, in CS6, it's been renamed the SWF Preview panel. It's misleading because some things it previews, like animations, don't work when exported to PDF!
The preview panel is for SWF only.