I initially connected the VCC and ground pins the other way round , could that have spoilt my TSOP1738?
I'm afraid so. Reversing the supply voltage will destroy most electronic devices.
The first thing to check is to power it (properly!) with a power supply and measure the current. It should be very small, around 1mA according to the datasheet. If it's more than that the part is broken. If it's absolutely 0.0000 (measured with a DMM) the part is likely broken.
The Gadget Shield
: accelerometer, RGB LED, IR transmit/receive, speaker, microphone, light sensor, potentiometer, pushbuttons