OK - I get this working now. If anyone interested, here you are:
val df = sqlContext.sql("SELECT * from table1")
val tempResult = df.filter(df("field1") > 10)
tempResult.write.mode("overwrite").saveAsTable("default.new_table")
val df1 = sqlContext.sql("SELECT * from default.new_table")
df1.show()
NOTE: the "new_table" table can but does not need to exist before writing to it