Unfortunately that is not possible because you have bought a phone that does not have wi-fi so it cannot use your wireless router.
If you want to use wi-fi you will need to sell the phone and buy another that supports it, for example the popular 5800 that looks almost identical to the 5230.
Other recent mid-low price models that support wi-fi: C5-03, C3-01, C6-01, X3-02, X5-01, C3-00, C6-00, E5-00, X6-00.