Well, first of all, if as you say:
"I have made substantial improvements which amount to much more than the gain I receive from the sale", then there is no capital gain to be concerned about?
However, if that isn't what you actually mean, and there is a capital gain involved, then in order to qualify for the exclusion ($250,000 if single or $500,000 if married filing a joint return), you would have to have owned and lived in the home as your principal residence for any 2 out of the previous 5 years ending on the date of sale in order to qualify for the exclusion.
There is no other exclusion available due to reinvestment of the sale proceeds, etc. as there has been in the past. There are certain exceptions to the 2 year requirement, but not the 5 year exception period. From your explanation of the time period involved, it sounds live you will not have occupied the property as your principal residence for any part of the 5 year period?
Perhaps you can clarify the time periods involved and whether or not you expect to actually have a capital gain or not from the sale of the property.