SYBASE Question with last month end date

Hi,
I was wondering if anybody knew something in sybase or some code that gave me the last month end date from a table. I kno oracle has last_day function i believe that can be used with sysdate-1.

I also wanted to kno if there was a way of doing something to get a query back between 2 dates. Lets say i did getdate()-1 and getdate()-3.
and getdate was dec... i would get sept oct and nov data.
But it should work also no matter what month. lets say i did this select next year feb ... i should get jan04 dec03 nov03

I have tried a few i keep getting data that isnt right ... hope somebody can help with something

Thanks in advance.