I'd go with a set of tubulars 1st. Disc brakes are nice when the conditions are bad but the tubular wheelset will show improved cornering and flat resistance (when running at appropriate psi) consistently.
Plus 1 for tubulars. I went to tubulars this season and I notice a huge improvement. I can run well below 30psi (I'm 185lbs) with no problems. Tubulars really help maintain tire contact with the ground and traction in all conditions. They also smooth out those jangly corners, which is not only faster, but reduces fatigue on the wrists and arms. Less fatigue = better endurance = faster. I've occasionally bottomed mine out with no consequences. Last season I pinch flatted my clinchers in a race. This doesn't happen with tubulars, you can actually adjust your tire pressure to what the course conditions demand, not just "well how low do I dare go".
Keep your bike and update your wheelset. Biggest improvement you can make in almost any cycling discipline is with wheels and tires and this is doubly true for 'cross. Keep your clinchers for training rides and gravel biking or whatever else you do, save your tubies for race day. Downside with tubies is increased hassle mounting them, changing flats etc, but that doesn't really matter for 'cross. If you don't ride them on the road, chances are you'll never flat them, they'll wear out first.
As for discs, well I think the jury on their utility in 'cross RACING is still split. Yes overall they offer increased braking performance, but do you really need it, and they add weight. You are not trying to decelerate from high speeds in the wet on pavement in 'cross. You are mostly just trying to modulate your speed going into corners. I notice a lot of discs scrape and are noisy, I don't think they are foolproof.
Let me put it this way, a lot of elite riders still use cantis, but I doubt many of them are not running tubulars.
Yes think I will keep my current bike and do the upgrade to tubular before next season, only one race left for me this year and everyone I talk to expresses same thing with the tires. Thanks for your feedback