Connecting to home wifi- which is 30m away from home

Hi (my first thread )

Heres the situation:

Recently I got a building built at the end of my garden about 30 metres away. I want to be able to access my home wifi down there and only get a really weak connection if I hold my laptop up high above my head. Theres quite a steep drop from my house to the bottom of my garden. I want to be able to connect from different computers/ laptops in my shed which is 30 metres away through wireless.Any suggestions you know that work. So far I have though about:

*Getting a new router as I have an old Belkin one (802.11g)
*Using homeplugs, (the shed uses the same electricity mains but has a sub- fusebox so I dont know if it would work)
* Ethernet cable from home to shed and put a second router in shed (though its quite a drop and I dont know if you can have a second router- also 30 metres of ethernet cable!)
*Wifi repeater (though it would have to go next to my router as the router is as close as possible to shed - 30 metres away!

*Any other suggestions/ reccomendations!

So I really want to be able to access internet but want the most reliable, quickest, cheapest (possibly), easiest method which will last. Any suggestions would be very useful. Thanks

ethernet cable is good for 100 meters.

homeplugs doesn't care about fuseboxes. it gets lost in transformers

I would use a yagi antenna and a wireless bridge and another wireless router, but I'm a geek and have boxes of each.

cheapest (possibly), easiest method : CAT5 cable

Hey Mark, thank you so much for being one of the main information sources on these forums. Ive read over your 101 & 103, granted its late and Ive had a couple drinks while trying to research a solution to my problem.

(cant post image till 5 posts)

Ive read some about connecting 2 wireless routers together but have yet to attempt it. I added 2 high gain antennas to the router inside the house, the signal cuts out just inside the main gate of the warehouse. I need to extend it inside another 10 feet or so, plus get through a drywall, with enough strength to allow 3-5 connected users to the web and network. Seems the boss had Ethernet ran from main building to the warehouse but very limited connectivity (and cuts out completely).

I have a decent understanding of computers and router settings.
Can you recommend a solution for me please.

Again, thank you for your time and knowledge.