Whilst it's true that the Hankook is the only one readily available in that precise size, there are plenty of other tyres available in sizes that give an acceptable rolling radius with a different profile of tyre. Obviously a different profile will change the handling slightly, and the speedo reading, slightly, but in a car like the Bis with relatively modest performance it's most unlikely imho that any use other than on the racetrack will detect these differences.
AIUI the standard bis rim is 5.5J x 13. Using the rim calculator here:
http://www.tyresizecalculator.com/tyre-wheel-calculators/tyre-size-for-rim-size-width-calculatoryou can get a list of 21 different tyre sizes that *could* in theory be fitted to that rim. Not all possible sizes will actually be manufactured, of course, and some that are manufactured may be inappropriate for various reasons. But that still leaves plenty of options.
For example, if you want to keep to a fairly narrow tyre to minimise scrubbing issues, go for 165. Then choose a low profile to keep the rolling radius close to original, say 55. Then a 165/55 R13 tyre will be 512mm OD compared to 519mm for the original. This is within the calibration error of the speedo, 2.5%, so would be fine to use. And if you google this tyre size you'll find Goodyear, Nankang, Falken and a load more besides.
I just picked one alternative size to see what the options are, but it won't take you for ever to work systematically through all the options to see what's the best choice. Best starting point is to just google each size in turn and eliminate those that are not readiy available. Then go back through the others and find the rolling diameter closest to 519mm. Then choose the narrowest of those still left in your list, to minimise fit issues.
When you get the answer, post it here so others can benefit from your efforts