Thai tourist Visa for foreigners residing in Hubei

My girlfriend and I (Colombians) work and live in Jingzhou Hubei and we want to go to Thailand in October holidays, we want to know if possible to apply for the visa via mail or a third party (agency), since there is no close consulate for us to go. Also, how long it takes to finish the process if we have to go to Beijing to apply in person and can only 1 of us go to the consulate with the documents for both of us. Thanks