I have played rugby quite a lot, it requires many different physical attributes.
First off, strength is key. I'll assume you have that covered fairly well, so the next thing is speed. Plyometrics are great, try stair/box jumps for something like 6x4 superset with squats or separately when relatively fresh.
You will also need to sprint; I would have one day a week of speed work (build up to around 4-6 flat-out sprints of 10-40 metres, finish with one-on-one tag or skills), and also a speed endurance/conditioning session (start with 50m/half pitch sprints with walk back recovery between reps, 3x5 with 3min. between sets).
Depending on how bad your fitness is, some extra running could be added after team training, just something moderate like 5 sets of twice the length of the pitch, 1min. between sets.
Max. speed and plyometrics sessions should be performed when fresh, but other fitness work should be after lifting on the same day.
Remember that skills come first when it comes to selection, keep working on it all.