Sorry, but you specifically stated that your BASIC was too slow and sluggishness is true for all BASICs I have encountered. I have no doubt that some BASIC compilers are slower and some are faster; however a 5 to 10 times speed increase from one to another is highly unlikely. If you have a problem with assembller try "C", it comes very close in performance. Another possibility is to fine your few busiest routines and (have someone) write those in assembler while keeping the rest in your preferred language.
Have fun
Erik Malund