If it is always "FAMT-" then for hypothetical field X, and assuming you want the number AS A NUMBER (vs. as a string), ...
CLNG( REPLACE( RIGHT( X, LEN( X ) - INSTR( 1, X, "FAMT-" ) + 5 ) , ",", "" ) )
If you didn't want a number but just a string, strip off the CLNG() and just use the rest. This is not the only way to do it, but if (for example) you have one of those strings where the trailing comma is omitted, the REPLACE won't do anything so should be save. If there is the chance that something other than FAMT- might be your marker, this WILL NOT WORK correctly.
Now if you REALLY wanted to do this safely and use it in a query and wanted control over options, the best method might be to write a public string function to take the whole field and return only that part that you wanted, doing the extraction a part at the time. Note that VBA is less efficient than the functions, but only slightly so, because doing the above in a query does involve the VBA programming environment as well.