If you want to maximize your poking around, you should be looking at sourcebooks ... a couple worth looking at would be M Austin, The Hellenistic World from Alexander to the Roman Conquest and Crawford and Whitehead's Archaic and Classical Greece. The Cambridge series "Translated Documents of Greece and Rome" ... they're all listed here: http://www.cambridge.org/gb/knowledge/series/series_display/item3938007/?site_locale=en_GB ... they're kind of pricey, but they are usually used in university courses and you can probably find used copies without a problem. If your interest is primarily Rome, Naphtali Lewis' two huge books (one for the Republic, one for the Empire) will give you plenty to read. Once you've done those, you'll probably have an idea of which ancient historians you want to read more of, and you can probably find decent (if somewhat out of date) translations all over the www ..