What to upgrade

I’m 2 weeks in I bought the VIP and strongholds almost to level 11 . I need a blue and green guy as I got 2 purple and 2 yellow what’s the fastest way to 3 stars or above I have one training camp to 9 when my strong hold levels up can I level up my training to get better heros?? What level will bring me 3* and up??? Thanks in advance

Training camp lvl12 will give you a guaranteed 3* while training camp lvl13 will give you a 3* with a chance for a 4*.
On the long term, training camp lvl20 will give you a 3, a 4 or a 5*.

This might help: https://sites.google.com/site/empiresandpuzzlesrpgwiki/intro/base/training-camps/training-costs

Thanks guys so train level 12 is my work up I need then !!!