Planning to move house best way to save towards the deposit

Hi All

I'm currently living a in a small flat which I bought for 38k two years ago. I my mortage was 32k with a 6k deposite. I'm hoping to move to a new house worth around 100k in a year or so.

I realise in order to do this I will need at least 10k deposite which I haven't yet paid towards my current mortage. I was wondering if it better to save 3-4k to make up the difference or should I pay say 3-4k into my current mortage over the next year?

Hope that all makes sence :)