Increasing the range of XBee with external antenna

I have 2 Xbee's (XBee Pro S2C). First XBee is Coordinator and 2nd Xbee is Router.
2nd Xbee(Router) is connected to Arduino(GPS is connected to Arduino) to send GPS data to my coordinator XBee.
Coordinator XBee is connected to my PC. I will check GPS data through X-CTU.

But the problem is range. I need 5km. How could I increase the range of Xbee? What type of antenna I should prefer?

gunesmadrali:
But the problem is range. I need 5km. How could I increase the range of Xbee? What type of antenna I should prefer?

The answer probably depends mostly on the distance you get at the moment, can you tell us that ?

Details of the actual project would probably improve the quality of the answers and help you get, we can only guess at where this '5km' is, and where it is (the surrounding environement) has a very major effect on achievable distances.

Be aware that its often the case that radio modules are set up to transmit the maximum legally permitted power into a plain omni directional antenna. Thus you cannot add 'better' antennas to increase range.

It all depends on the rules that apply in your part of the World, you would need to check.

srnet:
The answer probably depends mostly on the distance you get at the moment, can you tell us that ?

Details of the actual project would probably improve the quality of the answers and help you get.

Be aware that its often the case that radio modules are set up to transmit the maximum legally permitted power into a plain omni directional antenna. Thus you cannot add 'better' antennas to increase range.

It all depends on the rules that apply in your part of the World, you would need to check.

Currently working distance is 3Km in air (Open Area). Region - EURASIA
There are no buildings in the area with a diameter of 10 kilometers
What happens if I implement 900 MHz antenna instead of 2.4 GHz antenna to increase distance. What would be happens?

gunesmadrali:
What happens if I implement 900 MHz antenna instead of 2.4 GHz antenna to increase distance. What would be happens?

Is your particular XBee able to operate on 2.4Ghz as well as 900Mhz ?