Why does a query on 4 times more data take 300 times more processing?
You need to provide more information for us to be sure: the table definitions including all the indexes and other keys defined upon them, if any of the referenced objects are views rather then tables then their definitions too and those of their dependant objects, and the query plan (I'm assuming sybase can be asked to present you with that as easily as other DBMSs).

A super-linear growth in effort compared to data size usually means that the database is having to scan or partial scan one object for every row output from another. Another reason for unexpected time for lager data is that the data was previously small enough to all be processed in memory but with the new size the database is having to either read more from disc (this compounds very badly with having to scan something multiple times) or spool intermediate results out to disc or both.

We could hazard some guesses, but if you edit the question to include more info (query plan and table/index/key/view definitions) we can make much better suggestions with less guess work (and tell you have to interpret that information yourself if the same problem comes up elsewhere in future).