How much maintenance is payable depends on your circumstances, the child's mother's circumstances and any special needs your daughter has.
The rate is determined ultimately by the courts. Either you or your daughter’s mother may apply to the District Court to vary the amount of maintenance payable if you cannot agree it between yourselves. The court must take into account ability to pay. It won’t order maintenance of €100 a week if, for example, someone had no income other than social welfare.
The court takes into account all assets, liabilities, income and expenses of both parties. You have to swear an affidavit setting this out, as would your daughter’s mother. When you say you have equity in a house, is this a house you live in or rent out? This would be taken into account, as this may mean you either pay a smaller mortgage or receive rental income. It is irrelevant that you owned the house before you met, the court is only concerned with what you have now and your ability to pay maintenance at this point in time. It can always be changed again in future if circumstances change.