You can heat the top eye with a lighter (But not too close like JPS said). It should easily be removed when heated - be carefull, it will be warm.
You can then purchase another top eye matching the internal diameter of the broken one. Using a glue stick from a glue gun, heat the end of the glue stick and let it drip into the back end of the new eye. Place onto rod end and align. Should cure in about 30 seconds.
I always keep a glue stick in my tackle bag for situations like this.
Just be carefull removing the 'hibuild' (resin) over the eye. I use a stanley knife to carefully remove this first, being carefull not to cut the rod tip, before heating to remove it.
Stinker