Technique aside, the prices you have mentioned are nowhere near viable as a sustainable business model. I don't care how low your overheads are... once you have covered marketing, promotion, film costs, fuel, insurance and so on, not to mention your time, you will be losing money.
Attempting to base your fees on what someone else charges is equally shortsighted... you don't know what their overheads are, you don't know how much work they are doing... and in fact you don't even know if they are making money. If you are serious, build a strong portfolio without too much concern for profitability. Your work needs to be strong, as the fact it is on film makes it no better or more desirable than portraits shot digitally. Once your have a portfolio, or preferably before, write down every single expense you can associate with offering portraiture as a service: insurance, website, phone etc. These are your indirect costs, and they exist regardless of whether you are getting work or otherwise. Next, work out the direct costs associated with each job; things like film, fuel, the expense in delivering a print and your time.
Now divide your indirect (ongoing) expenses by the number of commissions you expect to receive in a year. Then add onto that base figure, which will be much higher than you have anticipated, the costs associated with a single job (direct expenses)... You now have a sum for the bare minimum you must make off each job, just to break even. And with the figures you have worked out at this stage, you are likely being way too optimistic.
I make my living full time as a family portrait photographer. Shooting film 100% of the time; expenses, time, insurance, tax etc all calculated, I could not make a living taking anything less that £1,000 average per job. I do now shoot a mixture of film (645) and digital (largely replacing 35mm) to maintain profitability. I also make platinum prints and frame, so take control of the whole process. I know how tough the market is, and I know that nobody much cares about the process unless they can see a difference in the results or cost.
If you charge too little you seem undesirable. You also don't make anything like the money you will need to advertise to the ideal target market - which you will need to find to cover your expenses. Perhaps I am jumping the gun with your intentions, but selling portraits successfully is a very hard market to crack... Best of luck!