When your mutual fund has been down and crashig in your ira?

i just opened my own ira a month ago i have not yet diversified it but i just bought one mutual fund for a few hundred to start my investing and for a week it was up then for the past few weeks it has been down .I do understand the market is up and down and that you have to diversify and have different sectors to bring in some income and growth when one fund is down another one will prosper ,so my question is should i hold onto this one fund its a international bond fund (after all i wont be taking out the money 27 years from now or so)so should i just hold and sit tight with this one fund or are there some other options i should pursue?