How can I boost my chances of getting into an astronomy or astrophysics program?

Goal: Astrophysics/Astronomy/Physics PhD

My current credentials:

Ugrad School: Temple University

Ugrad major: Computer Science

GPA: 2.9 (due to low first few semesters, later semesters higher GPA)

Research Experience: None

Letters of Recommendation: I am beginning the process of asking for letters from 2 of my comp sci professors and 1 from my current boss

Professional Experience: 4 years of software engineering internships and 1 of full time software engineer job

Practice General GRE Scores: 164Q/158V (I expect to score around these scores in 1-2 months when I take the real test)

Course experience in school: 2 Calc based physics courses (mechanics/e&m) with labs, a few algorithms classes, a few calc classes, a bunch of assorted computer science math classes

I am expecting to begin my applications around this time next year in 2018.

I have tried to talk to some local schools around me to ask for volunteer TA or research positions to no avail. I cannot get accepted to a masters physics program, because so far every school I've looked at only accepts students for a PhD in physics.

I have been told by previous astrophysics and particle physics PhD students who said I should be fine with a CS degree, as most of what they do is programming, and they said it may end up being beneficial to me getting accepted.

I am currently reading through 3 different textbooks as well as studying problems from previous years physics GRE exams, and I hope to take the exam sometime in the spring.

What can I do to increase my chances of getting accepted to a PhD program and getting a TA/research funded fellowship (I cannot to pay my own way through school)?

I am looking to stay in the Northeast US/SE Canada around where I grew up and went to Ugrad, but other than that I'm willing to go/apply to almost any university.

I also spoke to some people in charge of a few different schools' physics/astrophysics grad admissions and they said to just prepare to take the PGRE and study hard.