Sold a home from a Quit Deed

My father gave( QUIT DEED)  me and 3 others his house in February just before he passed.  It was sold in September for 700,000 from which I got a 1099-S for 176,000.  

 

1> Can I include as a cost basis 25% of the original purchase price from 1992 (200,000) that my dad paid?

 

2> Can I cost basis home improvements done by my dad on the property before he transferred it?

 

3> Do I need to prepay some federal taxes since it's such a big 1099?  If so, how much?