Upgrading a Radeon HD 5450 Need Advice

The purchase date is today. I've finally gotten the money together and am ready to do this. The budget range is $200-250. With less being better, obviously. Especially if I can go for a 2GB card for less than $200. But, it's not the holidays and I don't expect miracles.

The primary use is gaming. I will be playing the following kinds of games:

Skyrim (with mods, including graphic enhancing mods)
Witcher 2 (gameplay mods only most likely)
Metro 2033 (no mods)
Fallout 3 (mods)
Fallout New Vegas (mods)
XCOM
GTA V

I don't think I'll ever be running things like Battlefield 3 or Crysis.

Current GPU and PSU are:

ATI Radeon HD 5450 1GB
Coolmax ZX-600 600W Power Supply

Other System Specs:

Motherboard: MSI 785GM-P45
CPU: AMD Athlon II X4 635 Quad Core CPU 2.9 Ghz
RAM: 8 GB DDR3 SDRAM 1333 (PC3 10666) 240-pin Dual
Channel
Cooler Master Elite 310 Mid-Tower Case

My preferred websites for parts are tigerdirect and newegg. Though, I'm not opposed to other sites like amazon.

Parts Preference: I'm open to suggestions. I like ATI, but this computer has a bad habit of randomly crashing sometimes, and ever since the 13.1 driver update, it won't even leave sleep mode (I've had to turn it off). I figure either there's a bad sector in the hard drive, or the video card drivers suck. But I'm not going to give up completely on ATI.

Overclocking is a possibility, but not a must.

My monitor is a 32" LG 1080p tv with max resolution of 1920 x 1080.

My main goal is to really just run the games listed at max or close enough at 40+ fps on average. 60 is ideal, but given the CPU, I wouldn't be surprised if that limits itself to older games only.

Here are the cards I'm considering:

PowerColor AX7850 2GBD5-DH Radeon HD 7850 2GB 256-bit GDDR5 PCI Express 3.0 x16 HDCP Ready CrossFireX Support Video Card

DIAMOND 7870PE52GV Radeon HD 7870 GHz Edition 2GB 256-bit GDDR5 PCI Express 3.0 x16 CrossFireX Support Video Card

I understand there's the potential to bottleneck the card given the cpu, and I'm okay with that. Anything will be a step up at this point. And I may upgrade the cpu later, and in the meantime, just overclock it. Though, the upgrade also leads to a slight catch because of the motherboard. The motherboard can only handle cpus up to 95w. So the best I could upgrade to is a Phenom II x4 x960 and not a 965.

Anyway, any help, advice, or suggestions are greatly appreciated and thank you for taking the time to at least read this!