That's not "a really good graphics card"
It's essentially the same you already have.
If it HAS to be £40, that one is at least a noticably step above what you already have, but it's still not really cost effective.
The sensible solution would be that one, it will on average be almost twice as fast as the £40 card and supports DX11, which might make a big difference in Civ5.
but is this one u showed me nvidia, cause if i already have nvidia, will i have to install this
one new.