You could install a megarange freewheel with a 34 tooth granny, which would most likely require a long cage rear derailleur. Putting a triple crankset on is possible, and if you get used components it can be done without breaking the bank. You'll need a longer bottom bracket spindle, a triple front derailleur, and possibly a long cage rear. It can get costly unless you are patient and resourceful at finding used parts.