Transmitting into deep space

Hypothetical question:

For the serial transmission of a file - about 1 gigabyte in size - to a listener sitting in Andromeda Galaxy in a reasonable amount of time (hours to a few days) ...

• What kind of (maybe self built?) antenna would work best?
• How much electrical power (W, kW) and energy (kWh or MWh) would be required?
• Would lasers do a better job both from a perspective of costs and/or signal strength?

For the receiving end: Let's assume that our listener has access to an array of antennas or laser receivers similar to our deep space network or better (sensor-array floating in space?).