Sirjee, kisbat ke engineer ho aap, basic wiring isnt a very tricky procedure.
1 possitive and 1 negative and your done.
Your audio unit provides output for 4 different speakers. Getting rear wiring with front wiring is similar to having 1 wire for all speakers. You wont enjoy surround sound.
So in case the wiring isnt present you can install new wiring in under rs.1000 and 20 minutes.