Dustin,
Why bother to run ASCII to Raster in the first place? An ASCII file formatted like the one Tarun outlined, should already be recognized as a raster dataset. That tool is a legacy tool and was only needed for the days when we couldn't read ASCII files representing raster data as actual raster datasets. All you probably have to do is build statistics on the .asc file, define the projection, and it will render as raster data in ArcMap. To confirm this you can run the Raster to ASCII tool to output an .asc file. Then hit Add Data and browse to where the file is on disk. In the Add Data dialog your .asc file should already have a raster dataset icon.
If you don't want the data in that format, just use the Copy Raster tool to change the format.
Regards,
Eric