where can i find the amount of money I paid in tax on the sale of a property?

When you sell any item of "property" for more than you paid, the capital gains are reported on schedule D and form 8949.  The amount of gains you report on schedule D is taxed at a special rate of 15% or 20%, not the regular tax rate.  Your total tax is shown on line 16 of form 1040. However, the exact calculation of how much of line 16 comes from the capital gains is only shown in a turbotax worksheet, you would have to download or print the PDF for "all forms and worksheets" to determine exactly how much tax was due to the capital gains.

However, if your home is reported on form 8949, then you probably paid at least some tax.  And if you qualified for the exclusion but did not claim it, you can probably reduce your tax and get a refund by amending. 

There is not a particular line number that you can look at to see how your return would change if you amended it.  

If there was a gain from the sale of the property, then that amount may be excluded and removed from your taxable income.   Removing an amount reported as capital gains will recalculate your capital gains tax and income tax amount.  Then, that reduction in tax is what you could receive by filing an amended return.  

The best way to know whether it is worthwhile is to create the amended return and then decide if you want to file it or not.  Changing the income on your Federal return should also affect your state so it should be amended too.