Does a divorce take effect, and how should the wife respond, after the husband says: "By divorce, you shall go up now to get money from my brother," and the wife refuses to go up to get the money?

Your statement to your wife: "By divorce, you will go out and take money from him now," is an oath of divorce. The majority of scholars hold that divorce occurs upon breaking such an oath. However, some scholars are of the opinion that divorce does not occur if the oath-taker's intention was not to divorce, but rather to urge an action. In this case, expiation for an oath becomes incumbent. This latter opinion is the more preponderant one and was held by Sheikh al-Islam Ibn Taymiyyah and Sheikh Ibn Uthaymeen, who based their argument on the Almighty's saying: (Allah has already ordained for you [Muslims] the dissolution of your oaths) [Quran 66:2] and the Prophet's (peace be upon him) saying: (Indeed, actions are by intentions).

So, if you did not intend for divorce to occur, then you must perform expiation for an oath.