Im no expert but i dont think you can get a skilled visa over the age of 45 except in exceptional circumstances
There is a parent visa, not sure if there is an age limit on this or not? I think you have to have a permanent resident visa before they can apply.
I beleive the contributory one can take up to 2 years on waiting list, whilst the non contributory one can take 8 to 10 years! they only give so many out a year
heres the link for the immigration website
Family - Visas & Immigration