don't buy a higher level trainer. Regardless of whichever strategy you tend to use to develop talent, your trainer is only worth it to you if you can maximize the value that the trainer provides you through training. mistakes cost less with a level 2, but getting a player maxed will take noticeably longer. So you have to decide how serious you want to train.
Right now in D.V in the US, you probably won't make bot promotion. You can promote this season and probably again next season as the 2nd best team in a D.V league. don't expect that to last (in D.IV and definitely by D.III it will no longer be the case), and ideally you should put your team in shape to beat the few guys that are active within the D.V scene in a given season.