If upon your return you reclaim Jobseekers Benefit, and your new claim is not separated by more than 26 weeks from the end of your last period on Jobseekers Benefit, you will take up where you left off before you left. See here for full details of linking http://www.welfare.ie/EN/OperationalGuidelines/Pages/jb_jobseekben.aspx#part6
You won't be claiming your Benefit while you're away working, so you will have an extra 2/3 months left to claim, so your Benefit won't exhaust until September/October 2012.