Ok was doing quest and did this quest for a Rune wright. all 3 levels. Seen he can take 3 particular runes and make a different kind of rune out of it. Now since he's using 3 runes does it tale all available rune slots so you can't add any more? Or is this an upgrade to the weapon or armor and leaves the slots free for other runes?

It takes all three slots -- all or nothing.

Ok but any of the new ones worth it that he does? Or is it a waste of time and I shouldn't of wasted 30,000 crowns on the guy.

It's a matter of taste. Personally, I think most of them are useless. However I do think that the one that gives you a guaranteed Quen shield, without using any stamina, every time you enter battle is very nice, and I do use it. Mostly, though, what they offer is just too weak.

It's not really worth it. I think it's a nice addition, but it doesn't have that many advantages. If you have money to spare - go for it. If not, better save it for something else. Adding new "slots" to equipment is nice, I also used the "all armor is light" one, and I read some people are quite happy with the "added range for whirl/rend", so you might try that if you use those a lot.
I would have preferred it if you could put the runewright enchantment on your equipment in additon to using the slots, would have been far more of an advantage that way.

I wish that I would have waited before I spent the crowns on him. But I wonder if I hadn't if I would have had access to the runes and such for which he offers? Because I'll have to admit that he does carry some great runes and schematics. As for adding slots so far the Ursine Heavy armor I'm wearing I couldn't add no slots to it.

I think he carries some unique items, so yeah, it's worth it to give him at least some money to set up his shop.
You can only add slots to items that have less than 3 slots already (the Witcher gear always has this).
Example: you have heavy armor with 1 upgrade slot. You can now ask the runewright to add two additional slots (for a good chunk of money, of course).
You can now let the runewright use these slots to enchant the armor (e.g. the "all armor is light" enchantment) or just use them like you normally would. It can come in handy, I think it's one of the more useful things he offers.

Ah, sorry, should have been more specific - You can only add additional (max 3) slots to swords and the chest piece. Gauntlets, trousers and boots cannot get extra slots and can't be enchanted by the runewright either.
I agree, it would have been cool if getting 3 slots on them had been possible. I guess it would just make Geralt too powerful if he could use that many enhancements at once.