The performance ratings between the Intel Core i7-4770 processor's Intel HD Graphics 4600 integrated graphics and the NVIDIA GeForce GT 630 dedicated graphics card are very similar. And both of them are weak performers for viewing movies. A better performing dedicated graphics card would be helpful, but make sure it's not a power-hungry one that the power supply can't handle. The NVIDIA GeForce GTX 645 1 GB GDDR5 dedicated graphics card is what I use in my 4th generation Intel computers, and there are some very good deals on eBay. I'll leave you with the others here to answer your other questions and provide other advice.
Thank you, your advice will keep me busy for a while. I found that my power supply is 330 W, so that is not all bad, for non-gaming, I guess....