How much is outstanding on your current mortgage? What is the value of that property? Is it fully let or do you rent a room and live there yourself? Who is your current mortgage with?
Well then I'd say your income is fully commited servicing that mortgage. You qualify for around €200,000 if you were to repay it and move house but for €8000 it's not really worth it IMHO.
Don't forget the tax (e.g. income tax, stamp duty clawback if applicable, CGT etc.) and other implications of renting out a former PPR. You should not plunge into such a venture lightly and without weighing up all the pros and cons.