Okay, as an electrician I'm supposed to tell you, you're not supposed to wire up anything over 50 volts AC. So don't do it. I'm sure you're just asking as a general question.

Power calculation is P = V * I, where V is volts and I is current.

Therefore, I = P/V.

P = 1000w
V = 240v
and so I = 4.16 Amps

A 10Amp sugar cube relay *should* be sufficient.

As for your timer, I think you're wiring it wrong. What terminals? Where? What power going into those terminals? The timers should come with a datasheet. If you follow it, you really can't go wrong. If you're following the datasheet and blowing the timers, nothing personal but I think you should leave the wiring to an electrician 240v is dangerous stuff.
- A