Hi Anand,
There are a lot of things to consider to increase range of an IR link, but in general just increasing the IR emitters radiant intensity will be enough.
You can do this by increasing power to the IR LED, or using one with a higher radiant intensity at the same power levels you're driving the one you have now at.
An FET driving the one you have now with say 14-ohms series resistance may do the trick if your LED can handle the peak-pulsed current.
2 LEDs in parallel with each having a series limiting resistor may work too.
A couple of other things to watch out for are;
1) Match the LED wavelength to the IR modules.
2) Get the IR carrier as close as possible to the center band-pass frequency of the IR receivers.
If the IR receivers peak spectral sensitivity is in the 940nm region, then use a 940nm IR LED.
If the center band-pass frequency of the IR receiver is 38kHz, then get the carrier as close as possible to 38kHz. Those 2 things alone make a huge difference in range.
And shielding the IR receiver from ambient disturbance sources like direct (or indirect) exposure to sunlight, flourescent lighting, etc, will increase gain of the IR receiver, and help to increase range.
I've attached an app note from Vishay you might find helpful. If you still need help let me know. I do a lot of work with IR.
Something like the attached schematic should work for 2 LEDs in parallel.
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