The radio taxi are available throughout the NCR and the same can be available just on a phone call like:
Delhi Cab: 91-11-44333222
Meru Cabs: 91-11-44224422
Mega cab: 91-11-41414141
Generally they charge around 14 rupees per km in the NCR region. The cabs are generally with AC and they can travel from delhi to UP and Haryana also.