why not have a new chainset? it's cheaper and with different ratios, you'll get more range (says 44-30t)
8 speed would likely mean it'll be wider than the 5/6 speeds (which use 120 spacing, 8 speed generally 130).
the hubs you may need to change as it could be a screw-on one, so simply adding more may not be an option.
the derallieur, depending on the size of the cassette could need changing, especially if it's something like 11-28 which required a long derailleur to compensate.
why not have a new chainset? it's cheaper and with different ratios, you'll get more range (says 44-30t)
8 speed would likely mean it'll be wider than the 5/6 speeds (which use 120 spacing, 8 speed generally 130).
the hubs you may need to change as it could be a screw-on one, so simply adding more may not be an option.
the derallieur, depending on the size of the cassette could need changing, especially if it's something like 11-28 which required a long derailleur to compensate.