For the theory you need to allow for at least 6 months. Add on whatever for the flying. At least 3 months for the IR etc.
Validations are around but very hard to get. You must have skills/hours that a particular airline wants and they sponsor you for the validation. Again, very hard to get. If you had the minimum hours I doubt any airline will pay for that conversion.
in other words, going overseas (outside Europe) isn't a cheap option any more.