There seems to a lot of confusion here about the qualifying age for Pension Credit. Quite simply, it's the age at a WOMAN becomes eligible for her State Pension. That used to be 60, meaning that BOTH men AND women were eligible for Pension Credit at that age (because a man was treated in exactly the same way as a woman born on the same day as him). However the woman's pension age has gradually been rising meaning that, for example, I won't become eligible for Pension Credit until I'm 63 years and 2½ months old. (I was 60 in April last year).
You can check the age when you'll qualify for Pension Credit here:
https://www.gov.uk/calculate-state-pension/y
The age for a free bus pass is the same as the age for Pension Credit in England (i.e. it's rising) but has been held at 60 in the rest of the UK.
The PAYE tax system works on the assumption that you'll keep earning at the same level throughout the whole of a tax year. That means that if your level of income drops during the year you'll have overpaid Income Tax. If you're continuing to pay Income Tax that overpayment can be refunded by simply charging you less tax for the rest of the year or by an end-of-year refund. (However, given that we're not very far into a tax year, any refund of what you overpaid between the start of the tax year and your retirement will be very small anyway).
You'll have almost certainly paid enough NI contributions to qualify for a full pension, so there's no point in making any voluntary contributions. However if you take on employment (where your earnings are over the NIC threshold) you'll still have to pay NICs until you reach your own State Pension age (not that of a woman of the same age). Then you can submit a 'certificate of age exception' to HMRC so that you no longer have to pay them.
If you're on a fairly low income it might be worth checking (with your local council) whether you qualify for any discount on your Council Tax.
You're now eligible for a Senior Railcard, giving you a third off rail travel. It costs £30 for one year (available from staffed stations or online) or £70 for three years (online only). However some local councils offer 1 Year Senior Railcards, through their own offices, for less.
National Express offer a similar scheme, where a £10 card gets you a third off coach travel for a year:
http://www.nationalexpress.com/waystosave/senior-coachcard.aspx