Looking for wireless(rf) transreceiver

Hi! I´m building robot and i need a good wireless control to it. I had NRF24L01+ with 2.4Ghz antenna and range was 2 wall and about 10 meters. I might need little bit powerful wireless in that project. Do you have experience about radiotechnology? I also built 25cm antenna to nrf module (is it right if frequency is 2.4Ghz? i mean can this antenna even work?)

If u don´t have interest to read above, lets go straight to the point. I need wireless transreceiver with good range to my robot, and it HAS TO BE CHEAP! I´m poor guy so it has to be pretty cheap. If there is no cheap transreceiver with good range, i can build my own antenna to cheap transreceiver, but i need little help. Thanks.

T: Teemu

Do you have experience about radiotechnology?

I've used XBee Series 1 and XBee Series 2 models, with good results. The range is dependent on models. Pro models have more range. Chip antennas have the lowest range. Wire antennas are (much) better. External antennas are the best.

and it HAS TO BE CHEAP!

Oh. Well, never mind. You get what you pay for.

I´m pretty sure xbee is almost "best" choose in wireless world to Arduino, but it is so expensive. Maybe later when i have job and some more money i could buy something more expensive. I think you know 15yrs old don't have lot of money. If you really want know i have 150 EUR cash, but i´m not going to spend all for transreceiver. I think if I´m not going to find cheap transreceiver, I´m going to buy nrf and build antenna to it(but i need some help).

This is probably the best you can do for the money.

Any antenna you make most likely won't work as well.