I've achieved 1-99 firemaking myself on my HCIM. Took me 4-5 days of constant training.
If you are in a rush I can do the job in 3 days but the price would be higher. Probably looking at 50m - 60m.
If you provide me more time (7-10 days) I can do the job for 40m.
Please feel free to contact me through a pm if you are interested.