Where can I find a set of data of the initial conditions of our solar system?
Horizons Ephemeris generator can give you a planet's position and velocity vectors at a specified time.

This is one set of possible options:



Clicking Generate Ephemeris on that page will give you position and velocity vectors:



Above the position and velocity vectors are the Julian date as well as the more conventional date.

Wikipedia can give the masses of the sun and planets.