hi guys i just bought ff13-2 for Christmas figured i'd give it a try and it turned out pretty good...Didn't beat it yet but i just wanted to ask some questions and give a tip or 2 on what i found makes things easier in this game!!

So what monsters can be captured that help the most in battle?...

right now im at the Archyite Steppe and i found that so far the best i got is Urdimmu (dragon dog looking monster) is commando pretty darn tuff an can be leveled really good i have him at level 30 his strength is 339 and his magic is 303, he is a huge help in every battle he does the most damage. And i have cait sith as my medic, actually the only medic i ran into so far in the game, not very good tho but a big help to have another medic on my squad, And then as my strongest ravager i just found in the archyite steppe is buccaboo one of the goblin type monster, i don't have enough chips to level him yet but i got him at level 2 and his magics already 137.

and another question , does anybody know where i can find a better medic then cait sith?

Really I found the most useful monster unit in battle was any one that was a MED (Cait Sith, green/white chocobos, Flaninator etc), as that way I rarely had to Paradigm Shift Noel or Serah into MED to heal - the monster unit was usually capable of serving as full-time healer in most battles, allowing me to leave Noel as COM and Serah as RAV for almost the entire game. Usually it was only a boss fight that I had to Paradigm Shift to something else, in which case a COM monster is preferable (especially one of the Behemoth types, like Feral Behemoth, Urdimmu etc) as not only are they tanks in both def and attack, they also prove to be effective debuffers as well (their Feral Link attacks are essentially SAB in that they debuff the enemy).

As for the best type of MED monster, look for a white or green chocobo in the Archlyte Steppe ?? AF (if I remember rightly they're found down towards the south west corner of the map), as their healing skills are pretty good. A Flaninator (a flan type found in Augusta Tower 300 AF) is also very good for healing.

i tried goin down there twice.......both times a giant black cactuar appeared an kicked my ass?!? guess ill try an run from it next time....so strong like had to get it to 999% to stagger and com an rav attacks were only doing 1 damage...1, then he kills me with his first attack

I'm pretty sure there are some guides on this but when I played for the first time I just captured whatever I could and experimented. The game is not that hard after all, just make sure to avoid the tough enemies you might accidentally encounter.