If CIS wants more evidence, make sure your wife complies with the request. She bears the burden of proving your relationship is real and not a fraud for immigration purposes. Additionally the K-3 is not likely to go any faster than the I-130. Focus on the I-130 RFE response.
Times vary depending on the consulate, evidence provided and general administrative processing. It also moves more quikly if you work with an experienced immigration attorney who knows the ins and outs of consulate processing and the NVC.
Initial K-3 approvals are taking over 6 months, then you have to wait for the visa interview at your home consulate. You can check at www.USCIS.gov.
713-772-2300. All information provided is general in nature. Please consult with an immigration attorney with full details of the case.