Take the old unit off and take it to an auto electrical specialist or a motor factor. Don't take it to a silly car accessory shop. A factors or auto electrical place are used to dealing with the trade, so theres no messing about, you generally find them on industrial estates rather than on the high street, they won't be open saturday afternoon or sunday.
There's basically two types of winker unit, 3 wire and 2 wire, and different wattages. There are also electronic types that flash at the correct rate whatever the load on it. Ask them to match your winker unit. An electronics boffin could build you a winker unit from scratch for less than Daihatsu are asking!