A 7450 will never get you that. There's nothing you can except to upgrade. A 7450 is not a gaming card by any stretch of the imagination.
If you want to play BF3 on high settings @ 1080P. Your going to need at least a 7770 Video card or better. (Assuming you have no AA)
And since HP's come with Generic cheap chinese made POS Power supplies you'll need a new one of those as well.
I5 3570K@4~5.0ghz: Gigabyte GA-Z77X-UD3H:Corsair Hydro H110 :16GB Corsair Vengeance DDR-3 1600: x2 XFX Radeon 7950 @ 1100/1575 : Corsair AX 860 PSU: x1 WD Black 1TB HDD's: 90GB Agility 3: 960GB SSD : Creative Labs X-FI:Corsair 500R Arctic White Edition:3 22inch Monitors Eyefinity @ 5294x 1050 : Alienware Tact-X Keyboard: Razer Naga :Corsair Vengence 1500 Headset: Corsair SP2500 Speakers
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