Getting an approval is not going to bring your husband into the U.S. any sooner because, as a spouse of a permanent resident, he will not be eligible for an immigrant visa until his priority date becomes current. You filed I-130 in March 2012; immigrant visas are being issued to the beneficiaries of the petitions filed in October 2010. Your husband's place in the wait line is determined by the date of filing of I-130, not by the date of its approval. You have about 18 more months to wait; and expediting the processing of your I-130 will not bring the priority date any closer. Neither USCIS nor the National Visa Center has the authority to issue an immigrant visa in excess of the limit allotted by the Congress or to move your husband up the priority line. Considering your health, you might ask for your husband's admission to the U.S. on a humanitarian parole so he could be with you while waiting for his immigrant visa priority date.
Answered on Jan 29th, 2013 at 4:32 PM