Help with gearing

[Airun]

Pretty new to road. I have a basically stock Giant TCR Aero2 and problem is this:

Any sort of climb kicks my butt when pack riding or trying not to get dropped. I have 53/39 and 12/26 9 speed.
What would be the most cost effective way to get a lower gear ratio?
I've looked at cassettes and cranksets (currently Truvativ ISIS) but just can't seem to decide the best route. Nashbar has a house branded compact double for like $50 on sale that gets good reviews and would be a good way to test that route (I think 50/34 was gearing iirc), but can't make myself pull the trigger.
Any thoughts yall?

[rsutton1223]

The biggest climbing gains you typically see are with the cassette. Have you thought about moving up to a 11-32 or equivalent 9 speed rear cassette?

SRAM PG-970 Cassette (9 Speed) from Realcyclist.com