Heat transfert / PDE equation

I would like to draw the temperature profile within a sphere cooled outside, whose equation is as follows:

diff(T,t) = (k/rho*cp)*diff(diff(T,r)) + (k/rho*cp)*(2/r)*diff(T,r)
initial values: t=0 and 0<=r<=R T=294 K
boundary condition r=0 and t>0 -k*diff(T,r)=0
r=R t>0 -k*diff(T,r)= h*(T-269.25)

I have seen that the equation used by the model heat transfer in solids is different. What can I do to simulate my differential equation? Thank you very much for the availability.
If I use the PDE solution in general form, what initial and boundary condition I have to use?
Grazia