Azapa, congratulation on your first airgun disassembly!
Anybody can unravel the mysteries of airgun maintenance even without being overly dexterous (I for one am far from being a handyman

) or having a proper workshop and these pictorials are a great help, indeed.
As to the spare parts: the only online-shop that features a decent section on airgun spares ('ricambi oleopneumatici') is
TuttoPescaMare :: SUBACQUEA » FUCILI SUBACQUEI » RICAMBI OLEOPNEUMATICI :: However, if you do not find what you need there, you may encounter some language problems ...
Alternatively, you may want to contact Laurent Kalifa at
chasse sous marine.net, achat vente d'équipement et matériel de chasse sous-marine He sells Seac Asso's and may have some spare parts available (even though they are not shown in the online shop). Laurent and his staff speak English.
Unfortunately, I cannot confirm as to whether or not either of the two will arrange for a delivery to Chile and at what cost.
Cheers