Hi Sanjeev,

my 2 cents (paise) worth.

Operating 232 at 3.3V will not work reliably. The 232 produces +ve and -ve using a charge pump ckt. As such the magnitude of these voltages depends on the switching frequency, caps and the supply voltage. Hence, you may not meet the RS-232 signal (specs) requirements.

You wrote:
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I have only 3.7V Lithium Battery to power the circuit and this is the problem ,it is a Hybrid DSSS transceiver module 2.4GHz which works works on 3.3V Vcc and its to be interfaced to my Cygnal and then to PC .
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Why not use a transistor based RS232 interface ckt. Hardly, you need two transistors (assuming TX & RX) and few passives. This assumption is based on the fact that the Hybrid DSSS transceiver module has complete RS232 signals.