“So, you’re looking at around $45734 to offset against your salary.”
Just remember that this is a tax deduction, not a tax credit. So multiply by your current tax bracket, e.g. 30% of $45,734 = $13,720. This will vary depending on your filing status, number of dependants, etc..
If you’re not comfortable figuring this out on your own, you probably ought to see a CPA and go over your last few tax returns to get a better estimate. Perhaps even check out Rich’s company, Pacific Capital Associates http://www.pcasd.com/