laptop upgrade or replace?
 

I am thinking about replacing my laptop that I have had for 8 years now. It was my first laptop and still runs fine, but its starting to get bogged down and jammed up. I am starting to play a little more computer games and my laptop is barely meeting minimal requirements for a lot of the newer games.

I have a HP pavilion dm4 purchased in 2009, I do mostly internet surfing and youtubing but as mentioned I am doing a little more game and want something to handle that type of load. Is it worth me updating what I have? Or just getting a whole new unit? For any mods I would be bringing the laptop to a specialist to do any type of work/upgrades.

below are the specs of what I have currently

Processor 2.4GHz Intel Core i5 M520
Memory 4GB, 800MHz DDR2
Hard drive 320GB 7,200rpm
Chipset Intel HM55
Graphics Intel Media Accelerator HD (integrated)
Operating System Windows 7 Home Premium (64-bit)

I would like something that would be able to play this game or similar

http://store.steampowered.com/app/263280/
Recommended specs are as follows:
OS: Windows XP, Windows Vista, Windows 7/8 or 10
Processor: Intel® Core 2 Duo 2.5GHz or equivalent
Memory: 4 GB RAM
Graphics: NVIDIA GeForce GTX 470 or equivalent
DirectX: Version 9.0c
Network: Broadband Internet connection
Storage: 1 GB available space
Sound Card: DirectX® 9.0c Compatible

keep in mind I have very minimal knowledge of computer specs and what they mean, but I do know what I have can barely run this game on even the lowest settings.

thanks for your input