Are the capitalized gains in realized gains? Examples would be dividends. If you don't, then you can look into growth-oriented funds and only cash out when you truly need the funds.

An alternate way of investing in the S&P 500 would be to see which Irish (or possibly EU) companies provide goods and services to the top US companies. If their business is heavily reliant on US contracts, odds are their fortunes rise and fall with the US market.

A good idea is to talk to a fee-based financial advisor that charges a flat fee to help review your options. Then you can invest yourself.