The original texts (in Latin) of the various treaties constituting the so-called Peace of Westphalia are hard to find. Neverhtless there are several English translations available. See for exmple the article on the Peace of Westphalia in Wikipedia.
Treaty text - English translation, with keyword indexes
Treaty Text Text of the Treaty of Westphalia, translated into English.
Treaty texts The texts of the Westphalian Treaties (IPO and IPM) and some translations (German, French, English, Italian, Spanish, Swedish).
Treaty of Osnabrück (Instrumentum Pacis Osnabrugensis, IPO) in full text
Treaty of Münster (Instrumentum Pacis Monasteriensis, IPM) in full text
High resolution map of Germany after the Treaty of Westphalia