is there any way at all of upgrading these rare weapons as the damage is really low at 17

http://elderscrolls.wikia.com/wiki/Drainheart_Sword

no upgrading possible, it says.

there is a different ghost blade that can be smithed with ectoplasm

is this part of a quest or random loot ?

There's a sword, bow and I think a battleaxe that can be smithed with ectoplasm. I found them on my second playthrough. They are found in a dungeon. Not sure if it's only one dungeon or not. Enemies will be carrying them.

Look for ghosts and reincarnated dragon priests.

http://elderscrolls.wikia.com/wiki/Ghostblade

if yo udon't mind spoilers

I never seen ghost bow's or axes

thanks for the heads up looks like i have to gear up and venture off to windhelm