extend wireless AND wired network - Accesspoint with switch?

[clifftrees]

Hi,
My wireless n modem router with 4 ethernet ports is on the ground floor at the front of house (thick walls, doors, etc) near the BT socket. Previously I ran 15m network cable up 2 floors to the loft (office) for the main PC, as wireless is available, but pretty poor. I now want improve wireless availability in the loft and to extend the network coverage out to the shed at the bottom of the garden. I was thinking of a wireless access point with built in 5 port switch as the best solution? - that would certainly improve the wireless in the loft no problem, but if I chose one with a detatchable aerial, and replace with higher gain version I'd have more chance of reaching bottom of the garden? Also, I presume I would connect the 1 network cable (from the router) to the AP and I could then also connect the PC to the AP via short network cable, as well as having the wireless for other devices?
I am not sure if I have to go into any complicated aspects of the router or Ap configuration to do this?
Any advice/correction would be most helpful.
Cliff

[2o2o]

Access point are relatively easy to setup, the aerial you would replace rather than being higher gain (will do very little in reality) you would want a directional aerial to focus the signal in the direction of your shed. However if you have a power connection in the loft and the shed you may also want to look at powerline networking it does work better than wireless although not as good as wired and is probably your cheapest option.

[clifftrees]

Thanks for the advice.
My main concern, being ignorant about how networks and access points work was whether I could actually use the single network cable to the loft to "feed" the AP, and from there can I just plug in the short network cable from one of the other ports on the AP to reconnect/"feed" my PC in the loft (which is what the long network cable is now plugged direct into). And potentially, can I use the other 4 ports to hook up other devices to the internet by network cable? I don't know what the difference is betwen AP and other devices, like switches or whatever.
Yeah, powerline solution is actually where I started thinking about this - it could have been used both inside the house to extend network reasonably, but the shed is only connected to the house power by extension lead via an external power socket. I read somewhere the powerline approach wasn't recommended in this situation. But also the cost.