Tax / pension advice, please!

[MoneyMatters]

I am on a gross salary of £39,572, and currently accept £217 pre month in nursery vouchers, so not taxed or insured.
I ahve v little in the way of pension arrangements, no company pension, nothing substantial in any independent pension.

Whe DD goes to school in January, should i put my £217 pcm into a salary sacrifice pension scheme of some sort, and how does this work? Am I saving myself from going into higher tax bracket by having nursery vouchers at present? Can I save myself from going into higher tax bracket by having a pension scheme instead? Company offers no pension - except entitlement to a stakeholder pension, which I haven't joined.

I have a v small Prudential pension (pay £50 pm) and a pension/mortgage thing which I took out when I bought my old house and it was a tax effeicient way to get a pension / motgage. My state NI payments are contracted out to this, I think.

Any views? TIA.