With MKII, you wouldn't be able to play in any sanctioned events until Jan. , but Warjacks regain supremacy after that point. However...
To round out what you have right now, for not many $$, I would get a Skarlock Thrall (almost mandatory w/ Cryx), and maybe a pistol wraith or 2. If you want units, banethralls or 'knights are a good place to start. They are reasonably forgiving to use, and pack a decent punch. Oh, and of course, you will need Warwitch Deneghra's card.
An awesome list for 350 mangled metal is Deneghra, Reaper, Nightmare (Slayer is also good, for fewer points), and a Deathripper. This allows you to use Deneghra's long list of

-you spells, and the Reaper's Harpoon Drag to dictate the pace of the battle. Without nightmare, if you dont want to buy it yet, you can upgrade the Deathripper to a Defiler. (Check my mathing, I'm not sure if the points are 100% accurate, but you should have a few left over.)
When you go to 500, add in another Bonejack, of any type, a Skarlock, and 2 pistol wraiths.
Deneghra is one of (maybe THE) best offensive 'Caster in the game. Her spells are designed to sap and weaken the enemy, while allowing Cryx's natural speed advantage to encircle and kill. You don't want to attack with her directly, because she is quite squishy. Include lots of Arc-Nodes in this force; it makes her spells near-on inescapeable. While she is raining down magic from all sides, use the reaper to pull the enemy in, and then smack them with the slayer. The Skarlock gives you yet one more FREE spell per turn, and the pistol wraiths can paralyze enemy beat sticks. Don't be afraid to lose a big jack with this list; Deneghra has so many ways of capping an ass. Just stay mobile, attack from as many angles at once as you can, and keep her out of close range unless you are damn sure she is going to kill or set up the kill of the enemy 'caster.