Selling my investment property - Need advice

[Raj Acha]

This is our situation

• Bought our house in 2004 for 285k in NJ and i was living in that house till November 2017
• Rented at in 2018 (Bought another house and moved into new house)
• Planning to sell it - I am getting around 100k more than what I paid for the house
• Planning to invest in a retail business

I want to understand the tax implications and general suggestions. I was under the impression that you don't have to pay capital gain tax on 500k profit in a lifetime. 

I am looking to buy a retail business and runnin it. It may take few years but i need to have money ready for the business. I believe, this is a strong sellers market and i want to take advantage of it to get decent price.

My main questions:

• Is selling house in my case directly inccure capital gain tax?
• If i have to pay capital gain tax, do you have 3 years to reinvest this money to avoid tax? 
• Since i don't think like a long term investor, any other points should i think about before selling the home?

Thank you all for your time 

-Raj