Is it permissible for me to continue my work in mobile programming and downloading ringtones that include anasheed (Islamic chants) and songs, given our difficult financial circumstances and my father's large debts and the lack of other employment, knowing that a sheikh has temporarily permitted me this work until another job becomes available?

It is forbidden to work in anything that causes the use and spread of what Allah has forbidden, such as singing and music. This is the basic principle. The ruling is not changed except in cases of extreme necessity that threaten a person's life or cause him unbearable hardship, such as the case of one who is permitted to eat carrion or pork. In such a case, it is obligatory to limit oneself to the extent of the necessity only. If this work is the only opportunity, then necessities permit prohibitions, while it is preferable to leave this work, trusting in Allah, and search for lawful work.