Fibre - wireless, ethernet, homeplugs advice

[#1]

I have been using the Plusnet value fibre connection for a few months but lately have noticed many drop-outs in internet connection and variable download speeds.
I think the key issue is that we use a wireless connection, which I know is not ideal, particularly given the fact that the router is in the loft and the computer is generally on the ground floor. The modem is plugged into the master socket in the loft. There are a few other wireless networks nearby but I have changed the wireless channel to 6 in an attempt to minimise interference, although there is still some overlap when I view them using inSSIDer. Plusnet have confirmed that our actual broadband connection is very stable so it appears to be a local issue. There is the slight possibility that a new installation of Panda Internet Security could be causing issues, which I need to investigate, but I do think we need to improve the wireless situation too.
As far as I can work out the options for improving the connection stability (and also the speed) are either:
- move the router out of the loft and run an ethernet cable from the modem to the router. I would still probably have to use wireless to connect to the router, but it would be closer to the computer and not transmit the signal through two floors. I was thinking of running the ethernet cable down alongside the TV aerial cable from the loft.
- use a Homeplug system. I assume we would plug the router into a Homeplug in the loft, then use a second plug for the laptop downstairs.
Does anyone have any advice and suggestions as to what might be the best option? I know that new ethernet cable would be cheaper than a pair of homeplugs, but it would also be more awkward to sort out the cabling.
Thanks in advance for any help.

[#2]

I suppose the first question is how fast is your fibre and what is the speed of your network card
These are quite cheap http://forums.thinkbroadband.com/dslrouter/f/4138358-solwise-value-500-homeplugs.html

[#3]

I would even first try the simple option of moving the router to a point in the loft where  you are hitting it most frequently via wifi without a wall or chimney breast in the way.
I don't know about loft insulation materials but interior ceilings and floors are fairly transparent to wifi with brick walls of course being less so. If your router is wall mountable you might even want to consider attaching it to the inside of your loft hatch and drilling through the hatch for the power and cable to the socket. If you can get by with such a fix it is only going to cost you the price of a long cable with which to experiment. It would be no less unsightly than a smoke alarm after all.  Messing about with the angle of the antennae can also sometimes have huge effects when internal structures are making signals patchy inside a building
(I picked up a quality 10m ethernet cable for £1.05! in gamestation the other day. I spotted it in the bargain box as I was looking for a birthday present for a nephew)

[#4]

Thanks for the replies.
It's a 40MB connection but I'm not sure how to find out about the network card. We've tried moving the router further along the loft to see if that helps, but I think the next step is to get a much longer ethernet cable. Fingers crossed!