Perhaps you can you sodium fluoride as as substitute for calcium fluoride, but personally I wouldn't make this choice. Calcium fluoride is also found as Fluorite or fluorspar, have you tried searching with this name?
Sodium fluoride as hydrogen fluoride is very toxic, it permeates the skin and "steals" calcium atoms from you. The pain of this "burn" takes some hours to arrive, it may lead to a heart attack (I think).
To make calcium fluoride from sodium fluoride, just add calcium hydroxide until you see no more precipitant.
the reaction:
NaF (aq) + CaOH (aq) -> CaF (s) + NaOH (aq)
Edit:
2 NaF (aq) + Ca(OH)2 (aq) -> CaF2 (s) + 2 NaOH (aq)
