Are you getting social welfare at the moment or still being paid? If not yet getting social welfare then you would be better off (I think!) to at least start drawing that as soon as you are able to and then immediately apply for the Short Term Enterprise Allowance, that would give you the option of doing the self employed thing but still retaining the approx 9 months Jobseekers Benefit payment.
I am assuming you do not mean actual dole which is Job Seekers Allowance and is the means tested one, if you have been working continuously for the past few years paying PRSI then you should qualify for Job Seekers Benefit which is not means tested but is just short term after which you could apply for JA but again it's means tested so depends on your situation and anything you are earning from self employment will be taken into account plus of course you must be available for work which depending on how the other job is structured might be hard to do.