Upgrade CPU or new laptop

I have a Gateway with a 1.86 GHz Pentium M and am looking to upgrade it to the M 780 (2.26 GHZ). I can do this for about $150. I have read several posts that say that practically any Core 2 Duo will outperform a single core CPU. I believe this, however I think it's very important to say that the only thing my Gateway does is run a single process called PS3 Media Server. Anyone who has a PS3 and uses PS3 media server knows how awesome this program is; but it is also very very CPU intensive. I cannot even scale my videos to 1080i or 1080p because at 720p my poor little single core is at 95-100% utilization.
So I am wondering a couple things:
1. How much better performance will a Core 2 Dual give me over my Pentium M when I am only running the single PS3 media server process?
2. Will the 1.86 to 2.26 jump be enough to handle the PS3 Media Server process effectively?
3. If not, what laptop/CPU should I be looking into?

It's important to remember this laptop will only be used to stream media. It is not a gaming, or even a multi-tasking laptop. That's why I thought it might be more cost effective to just upgrade the CPU, however if the Pentium M 780 still isn't going to give me the performance I need them it's a waste of $150.

Have You considered getting a new desktop instead of laptop?

why not run the PS3 server on the existing desktop?

Since the newer CPU is only about 20% faster, I don't think you'll see much practical difference. Also, IIRC the Pentium M wasn't so great on multimedia, so I'd expect any current dual-core laptop to smoke it. A modern laptop will also have more RAM, and probably a faster hard drive, both of which should help as well.

This Acer w/T3400 CPU and WiFi-N runs about $450: http://www.staples.com/office/supp [...] 1_SC3:CG71P4118:CL161747