Andy is right- mealworms are not a great staple food- too high in fat I believe. If your pet store does not carry blackworms, you could perhaps ask them to order them for you. You can also try frozen bloodworms (mine don't like them but others here have better success with them), Earthworm are probably the best choice, I've found my eastern newts love live food more than frozen, freeze dried or pellets.
Try to keep the water (and room) temp lower. it's a real challenge, especially during the summer months, but I try to keep mine below 70 F whenever possible. I keep the AC on while I'm at work and at night. the newts can definitely act stressed if it gets warm. Even 72 is getting up there- the cooler the better. I keep jugs of tap water (let sit at room temp for 24 hrs) in my fridge, so if the water gets warm, I dump some out and replace with the cold water. Of course, you end up doing this everyday (and several times a day if it's really hot). But, it's better than stressed newts.
For a filter, I use a duetto 50, which is great because it doesn't dissipate too much heat and it has an adjustable water output. I don't think eastern newts like water current that much so you can adjust the output to a gentle water flow. There are other great filters out there too.
This site is great- you can always do a search for whatever you have a question about and find out new info. Good luck! I know my newts bring me much joy and I hope your little one does too!