Converting from Text to Date

Hi

all,

How can I extract out from a date field the month and year arguments and create a new coloum with the format:

mm\yyyyy

I have an original date column ("minnipuk") holding the data in a dd/mm/yyyy format.

what I need is - 9-2015 or even better sep-2015.

I did a new measure: in the query editor 

                                                               Text.From(Date.Month([minnpk]))
                                                                &"-"
                                                                &Text.From(Date.Year([minnpk]))

but when I used it in an x axis inside a graph the data is not sorted correctly (9-2016 comes after 10-2016  ), and  I think I understand why:It's a text not a date.

Is it possible to make the new column I have created a date type?

Should It be done in the query editor or inside the report itself?

Thanks

Erez