You can go with G05, which will require a complete flush. Upside: guaranteed no antifreeze-related problems. Downside: G05 is kinda expensive and hard to find.
Or you can stick with Dexcool. Upside: cheap, easy to find, will keep the system spectacularly clean so long as nothing goes wrong. Downside: will degrade certain plastics, and will produce copious amounts of sticky, nasty, radiator-clogging sludge under certain less than ideal (but fairly common) conditions.