I looked a round wowwiki and couldn't find what i was looking for.. I'm not a programmer and i lack in the macro department..

What i need a macro to do is to cast Lifebloom on my target, then should i repress the macro button cast lifebloom again on my focus target. If possible, the macro to have a 5sec cooldown.

So what i have so far is:

/castsequence reset=5 [target=target] Lifebloom, [target=focus] Lifebloom

would that work?

This would not work, a cast sequence only accepts conditionals at it's start, not on any individual spell cast within the sequence. I can't actually think of a good way of making a macro that automates casting Lifebloom on two different targets. At least, not without using up your normal target frame and using /targetlasttarget, which is simply impractical, for completeness sake, I'll still post that option:

/targetlasttarget
/cast Lifebloom

This would work through targeting one person first, then the second person you want to use this on, and then simply using the macro, which should switch between these two players and cast Lifebloom on them. Any other healing you'd do would have to be done through a clickcasting mod however.

Another thing that could be tried which might work (Or might not work at all), would be something along these lines:

/castsequence reset=5 Lifebloom, Dummy Spell
/stopcasting
/castsequence reset=5 [target=focus]Lifebloom, Dummy Spell

The Dummy Spell is in there to basically force WoW not to cast a spell, and thus allow it to fall through to the second /castsequence. But I have no idea whether this'll work, it's just as likely to not work at all.

I'd also recommend installing some kind of error suppresion mod if you're going to be using this.

There's a checkbox in interface options to suppress LUA errors now. Unless that showed up via some ninja mod update I did through WAU.

I wasn't talking about LUA Errors as much as "top of the screen" errors (Like "Spell not ready yet" etc.).