New head with old block

i need a realistic answer on what to do next. i got my head resurfaced with new plugs,seals, everything is new... 2 weeks later i replaced oil pan and gasket, filled it up with fresh oil and new filter, drove around town and the timing belt snapped off. my friend said its the oil pump so i bought a new one with a timing belt too but not sure what to do....

is it better to replace the whole block or replace one part at a time???