The biggest problem with that laptop you already have is the hard drive. A 5400 RPM hard drive is just too slow for gaming. It actually has a decent video card and a decent amount of ram.
If I were you, what I would do is buy an 80GB Solid state hard drive for $200 http://www.newegg.com/Product/Product.aspx?Item=N82E16820167023
160Gb variant is $360
You need to stay with a laptop either way, and that would give you an enourmous speed boost for loading "in" specifically. If that doesn't fully solve the issue, keep the drive and get a better system a little down the road.
If you decide to replace the computer entirely, I would go with a Dell Precision M4500 as they are currently on sale for around $1300 with a high end Nvidia card. http://www.dell.com/us/en/business/notebooks/precision-m4500/pd.aspx?refid=precision-m4500&s=bsd&cs=04
Edit: several reasons for that reccommendation. 1, it has a docking port so if you are on the road alot, less cable wear and tear plugging things in. 2. Nice screen and nice video card, 3 great parts availability, will be able to keep it repaired for years if needed even out of warranty, and 4, very solid case and screen hinges.
Hm, so you would definitely recommend the Dell M4500 over the MSI? I'm a noob at reading this but I don't even see the Nvidia Quadro FX 800M on the benchmark chart - whereabouts would it place? http://www.videocardbenchmark.net/high_end_gpus.html
Anyway, I customized the Dell PC to be close to the price of the Newegg. Here's what I came up with for $1,384.
PROCESSOR Intel® Core™ i5-520M Dual Core 2.40GHz 3MB edit
OPERATING SYSTEM Genuine Windows® 7 Professional, 32-bit, no media edit
OFFICE SOFTWARE Microsoft® Office Starter 2010 edit
WARRANTY & SERVICE 3 Year Basic Limited Warranty and 3 Year Next Business Day On-Site Service edit
VIDEO CARD NVIDIA® Quadro FX 880M Graphics with 1GB dedicated memory edit
MEMORY 4.0GB, DDR3-1333MHz SDRAM, 2 DIMMS edit
LCD 15.6" HD (1366 x 768) Anti-Glare LED Display edit
SECURITY SOFTWARE Trend Micro Worry-Free Business Security Services, 30-days edit
HARD DRIVE 250GB 7200rpm Hard Drive edit
OPTICAL DRIVE 8X DVD with Cyberlink Power DVD™, no media edit
BATTERY OPTIONS 9-cell (90Wh) Lithium Ion Battery edit
WIRELESS CARD Dell Wireless™ 1501 802.11b/g/n Half Mini Card edit
MODEM No Modem edit
CAMERA/MICROPHONE Integrated webcam with microphone edit
INTERNAL KEYBOARD Internal English Keyboard edit
FINGERPRINT READER OPTION No Fingerprint Reader and No Contactless Smartcard Reader edit
PRECISION ON No Precison ON edit
My Services & Warranties
ALSO INCLUDED WITH YOUR SYSTEM
DELL PRECISION M4500 BASE Precision Mobile M4500
A/C ADAPTER 130W 3P, A/C Adapter
Bundle Solutions Mobile Edge Ultra V-Load Briefcase - Laptop carrying case
Systems Management No Intel vPro™ Technology’s advanced management features
Processor Branding Intel Core i5 Label
SYSTEM DOCUMENTATION No Resource DVD or Quick Reference Guide
Is this really gonna serve me better than the 17" i5 with the ATI Mobility Radeon HD 5870, which I can get for $250 cheaper?