Just get some satellite cable and a couple of F connectors and extend the cable yourself, just take care when making your connectors to makesure the inner and outer of the coax are not shorting etc.
If it doesn't work then put it back as it was and have a little look on ebay for some custom made lengths of the correct cable with connectors already fitted for you
Alternatively pay £99 for a tech to come out and do it for you.