It appears, if you don't mind me saying so, is that most of the problem is with your expectations: I'm going to try some amateur pyscho-analysis now, hold on to your hat
If you're buying the very top-end kit, then you're going to notice every little glitch and hiccup, and you're going to be thinking of ways to go for even 'better' kit to counteract it.
If you spend a grand on a laptop, then you're going to fall into the same trap - you've bought something 'high-end' (a thousand quid will buy you a lot of laptop, even if it's not the very best), and you're
still going to expect very smooth and fluid gameplay and you're
still going to hate every time it doesn't meet your expectations.
So can I suggest a different approach?
Buy a cheap laptop. That way if your game glitches, or you can't run it at the very highest settings then you'll think 'never mind, it's only a budget system' (and a not very upgradeable one at that) rather than worrying about what more kit you need to buy. You can get a Dell with WinXP and an 8600GT for £400-£500 that'll still let you play pc games, but you'll have totally different expectations. Instead of 'oh noes my framerate dipped below 75fps for 12 nanoseconds' it'd be 'cool, my rubbish laptop is still getting 40fps, or 70fps if I run it at Low settings'
And then go buy a PS3 or an Xbox360. Hell, for your saving on the laptop you could buy both! You can't upgrade those, and you know you'll be playing on a level field with everyone you play against on-line.
Oh, and get a Ninty DS. And a Wii, cos they're fun, and very different from playing yet another generic FPS or RTS.
Just take a big break from PC gaming, and work out your true priorities. Maybe you'll have to jump back on to the upgrade bandwagon in the future, but it'd at least be a bit more exciting if you've missed a few incremental upgrades and get to buy something
truly new and different