Extending Wireless Range

I want to extend the range of my wireless to cover outside my house, on one side about 50m to my garage and on the other side about 15m to an outdoor entertaining area.

 

The current wireless modem sits in one corner of the house, direct line of sight to the shed with just a window in the way. I can just get 1 bar signal outside the shed (colourbond walls) but nothing inside the shed.

 

On hte otherside the signal has to go through two mud brick walls. Immediately outside the house I still get 1 - 2 bars but a few metres away it rapidly drops to nothing.

 

Can someone suggest the most appropriate product I should look at?

 

Thanks

 

Marty