I sent you a friend invite on Steam to help you out, but you didn't accept. Guess I'll continue posting here!
Man, a 1070 is a lot of money down the drain for only playing TF2.
I forgot to ask what case you have. I'll go with mATX for now!
PCPartPicker part list: http://pcpartpicker.com/list/rRzg99
Price breakdown by merchant: http://pcpartpicker.com/list/rRzg99/by_merchant/
CPU: Intel Core i5-6600 3.3GHz Quad-Core Processor ($213.99 @ SuperBiiz)
Motherboard: Gigabyte GA-H170M-D3H Micro ATX LGA1151 Motherboard ($89.88 @ OutletPC)
Memory: G.Skill NT Series 8GB (2 x 4GB) DDR4-2400 Memory ($39.98 @ Newegg)
Total: $343.85
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2016-09-25 23:50 EDT-0400
i5 6600 since clock speed in TF2 matters and you don't have a tight budget. New RAM because DDR4 on Skylake, and unless if you have a valid reason for more than 8GB of RAM then it's best to save the $30-40.