Ca capital gains tax-how much will I lose?

[Yern Chao]

Unsure about Ca capital gains tax.

My scenario:

Bought a duplex 13 yrs ago for $237,500 but haven't lived in it for the last 6 yrs. want to list for $350,000. Will I be paying capital gain tax federally and through Ca? 

I am married and file jointly. Our last years taxable income was a low of roughly $40,000 since we started a business.

Based on my general calculation (not including deductions to make it easier for my understanding) we'll gain $112,500. 

Are we paying capital gains tax based on the $40,000 bracket (0%) or are getting taxed on the $40,000+112,500 (15%)?  

We are looking to reinvest some gains (probably $65,000) into our business not related to real estate. 

When do we pay the taxes? At tax time or when we get the $?

Thanks in advanced.