After my attack i use the focu and get a TL. Can i use that TL on the same attack or must i wait for the next round?

You can use the Target Lock during this attack.

If you somehow have more than one Focus Token and the thing that triggered R4 was spending a Focus Token for its default effect (converting [eye] results to [boom] results), you won't be able to spend another Focus Token to convert any [eye]s you get on your Target Lock reroll, though.

Per the FAQ:

So, one step further.

Example 1 - Let's say you have TLT and 2 focus tokens. By the wording on R4 and looking st the flowchart for attacks this should be true:

Declare attack w/TLT -> roll dice -> spend focus -> acquire R4 TL -> use TL -> resolve down to step 7 on the attack flowchart then proceed back to step 2. And if you have a second token you can do the exact same chain again.

TL;DR

2 focus w/R4 and TLT = 2 focus and TL modded shots per round

Example 2 - you have a TL and focus and fire a torp that requires you to spend the TL.

declare attack, declare weapon, spend TL -> roll dice -> spend focus (even w/o eyeball results) -> acquire TL -> use TL to modify dice -> use guidance chips to modify one die

TL;DR

TL/focus/GC/R4 will give three mods, even when spending the TL to fire the torp

Sound right?