Faster way to Upload

[TechWeb]

I upload about 15000 rows each of 5 cells at a time.  For this, I find the 
api (with cell based batch method) to be slow and unreliable.  Is there any 
way to upload an entire sheet at once.  Maybe upload a .csv and somehow 
specify that it should be "imported" to create a new spreadsheet.  I 
essentially just want to replace the contents of the old spreadsheet.
    Thanks