theres a few parts you need for it m8

the rebore anything from 25 to around 40 quid depending where you go mines just cost £37

os piston and rings clips an gugeon pin beetween £32 £42

small end bearing £ 4.50

gaskets maybe cheaper but definetly use the black top end search tdr gaskets instead on ebay £20

or you could have a total cheap out on it m8.  an just replace your rings  if ya cylinder bore is completly fine an piston still in good nik,,,  not the way to go tho