Financing Question please help!

[Edison Estrella]

I really need some help here. We are sitting on 500k cash. We’ve been saving for years in order to invest in real estate. We live in NYC (Queens) which makes every house purchase very expensive. 

Here is my problem and question:
So I conduct business out of my 1 family house. (Can’t relocate due to regulations). 
Which will easily pay off the mortgage and leave me a cash flow of around 3k cash by keeping the business open for the foreseeable future. Which in my eyes it’s a no brainer. However buying this house will mean that I will lose all the benefits of acquiring a home with 5 or 10% as a first time home buyer. Im thinking of buying this house which will cost me around 80k giving 10% down- this house it’s already not confortable for my family and will have to buy another house in a most 3 years.

How much will I be looking in terms of down payment for that second home? And I will like to keep this house for my business use. 

Please advise! Thank you