Hi
You may invest in a residential house property upto March 22. In case the investment is not made till actual date of return filing or due date of return filing, whichever is earlier, the deposit into CGDS is to be made.
Since the date is extended for return filing and you're filing your return on, say 30 Nov, you may deposit in CGDS account before 30 Nov.
If return is filed before, deposit has to be made before that.
You may invest in 2 properties provided your capital gains are less than 2 crores and you have sold a residential house property.