Well, am not familiar with the machine or control but it should be worth at least 5g.
That tooling would cost $2500 to buy just by itself.
If it truly is 2.5d that would mean that 3 axis work is only limited due to limitations of the control. A control upgrade would give you 3 axis capabilities without needing to upgrade the machine.
Most CAM software programming in what they consider to be 3D truly is only using 2 axis simultaneously anyway. It is probable that that control only allows G17 plane moves and will not accept G18 or G19 plane moves. you could still do some decent 3D machining using Z level type 3D programming.
Coincidentally FreeMill by MecSoft is limited to this type of 3 axis programming anyway (convenient for you if you wish to do that).