This is the most common problem being faced by genuine buyers such as you.
This coming september 2015 the delay will be around 2 years,
as per sale agreement has the builder provided a clause if in the event of delay beyond the agreed period, the builder agrees to pay delay compensation or not, if it is provided for then the builder is liable to pay that particular amount, if he has not included the clause then also he is liable to pay compensation on an amount that will be determined by the courts.
You can file the complaint before the Consumer court with a fixed court fee of Rs.4,000/- maximum and seek compensation upto 1 crores from the builder under various heads, time frame for a decision/judgement from such courts would be approximately 1 1/2 years (here in bangalore)
this apart you can also file a civil suit in the Civil Court demanding the same amount together with court costs etc., but the major draw back would be that you will have to pay substantial court fee on the amount demanded from the builder and the matter is likely to be resolved in 5 to 10 years minimum.
Firstly issue a legal notice through an advocate, if he fails to pay delay compensation, then file the complaint before the consumer court.
to make the case strong contact a good consumer advocate who deals exclusively in such matters.