Why get a new guitar when the problem isn't the guitar? You're just going to make the same mistakes on the new one. Say an OK new guitar costs £200. £20 will get you an hour with a novice teacher, or half an hour with a really good one, and one lesson a fortnight is plenty to practise what you've been taught. So for the cost of a new instrument, you've got 5 months worth of lessons. And this is for a pretty cheap instrument. If you're suggesting getting something decent, say £600. Now you're looking at over a year's worth of lessons.

Sure, ask your teacher to check your guitar - it might be that the frets are worn or the action is too high, in which case you might legitimately want to do something about it. Or if you have some condition which makes your guitar harder to play (eg. if you've got small hands or arthritis and your guitar has a wide fretboard). But otherwise, there's no point blaming the tools if you already know you're a poor workman. ;-)

Graham.