Hi
To be honest, I haven't integrated First Data into any oscommerce so far, but I've built a lot of custom payment integration modules (you can look into my past projects, some 4-6 years ago) by using the payment gateway provided documentation. If you could please send me a link to your docs I should first have a look on it and see if my bid is proper for the amount of work that needs to be done, then I'll confirm and/or change it if need be. As for the estimated timeframe, I'll have the module ready for the first tests in 2 days, and then, hopefully if not much trouble with it, the 3rd day it'll be ready to go into production mode, live on your website. Please just let me know, do you need the oscommerce or the creloaded version of the module, or both of them ? Technically there are not many differences, but there are, though, some that could render the oscommerce version not usable on creloaded. And, what creloaded version/type do you have there, please ?
Regards
Dragos