ull have to measure the speaker wires
as for extension cable .. just goto any ELECTRONIC shop and ask for SPEAKER CABLES in lay mans terms
theres just one kind of them
ull also get necessary plugs at an electronics shop .. IF needed !
that is if ur speaker cable ends have plugs instead of wires
these speakers use RCA connectors
so ull need 2 female rca and 2 male rca plugs. ..
[EDIT]
sorry u arent form mumbai so the shops info wont matter