Guh, childcare is SO expensive and it's the number one reason I never went back to work properly. Though now I work from home and it's slightly the worst of both worlds with a two year old and a four year old. Bring on January when they'll BOTH be in 16 hours free nursery a week.
Aaaaaaanyways... Look for a nursery RIGHT NOW and out your name down if you like it. Pay the fee. Depending on your standards and area, it may be hard to get a spot if you're looking for one to start in just a few months' time. Remember, yes - it's expensive, but it's what's expected and it doesn't put people off.
A childminder won't be any more expensive, though a nanny, if you've just one kid, may be a bit pricier. Plus, you count as their employer and have to pay their nat'l insurance, I think. Something along those lines.
Tldr - find a nursery you like now and put your name down immediately.