Do not '' invest '', you need your hard earned cash to secure your own roof over your head, making an investment over such a short period is daft, it would not be an investment it would be gambling and please don't place your funds at risk.
Suggest you ensure you are getting the best return on your deposits with Ulster and BOI, also take a look at the excellent best buys in the Deposits section.
You are in a great position to take advantage of the housing market, I suggest you shop around and seek an approval in principal from a lender to allow you shop for your dream home, approval in principal simply put means a lender ( Bank / Building Society ) would be prepared to lend you €xxxxx euro over say 20 years on a sample property.