Webfont issues and CSS fallback

Hi,

When viewing my site http://studiomoran.com/ on my machine, all the fonts look fine. They should be set in 'Graphik' a font I have hosted as a webfont.

When I view via an iphone or when my wife views on her machine the fonts change to a mix of Helvetica Neue and Times.

Any ideas on how I can solve this please? Worst case scenario, a fall back to Helvetica Neue or the google font Karla would be preferable.

Thanks in advance