Well, the easiest way to exted the Cybiko's range is an antenna. A 902 - 928 Mhz compatable antenna is required. These range from $30 - $500.
There are 2 ways you can go by about this. If you know exactly where your cybiko is going to be within 10 degrees left or right you could use a directional antenna (ie. Yagi antenna) which offers higher gain (The antenna power) and are cheaper. Most people want to be mobile. If your like me get a omni-direftional antenna. This offers a 360 degree radius. The downsides are that they are more expensive and offer less gain.
My Home Brew 4 dbi Omni - Directional Antenna