Long Term Capital Gains Tax

Dear Sir, I am investing in a new property and have made 20% downpayment on the construction that is due to start in August 2015 and will be completed by around March 2019. The sale agreement will be drawn somewhere around August 2015. Part of the proceeds for the purchase will come out of sale of existing property that is in my mother's name. Do note that the property is not yet sold and we are seeking buyers now. The property will be co-owned by my mother, myself and my spouse. The payment will be approximately in the following proportion, - 50% to 60% from the proceeds of the sale of the existing property - Remaining from myself and my spouse including a loan Could you confirm if the sale of the existing property and the date of the sale agreement need to be timed to enable maximum time period for investment of the capital gains from the sale? I believe if the new property is bought after the existing property is sold, one has only 1 year to invest the entire capital gains? However, if the new property is bought before the existing property is sold, one has 2 years to invest the capital gains. I may not be accurate with my understanding here. Please do clarify. Do let me know if you need more details. Thank you in advance. Sudeep.