1) No, spouse of student cannot accompany the student. Also, even if s/he did, an employer must sponsor a work permit for the spouse, the chances of which are very slim in the current labour market (Ireland's current unemployment rate 12.3%)
2) Post MBA stay is provided for 1 year
The chances of immigrants (from non-english speaking countries) finding an "MBA-worthy" job in the current marketplace
is very slim. Post MBA options here is all about your connections (network) and less about the degree itself (ie., its not really a meritocracy). Check this post again in a week, I'll post some useful articles that you must read before you put your hard earned money down on the program.