Replacing HDD but keeping it as external storage.

[ColinLaybourn]

Hi guys.
I've been doing quite a lot of gameplay capture and video editing for my son's YouTube channel but I'm using a very basic 2 year old hp notebook and its not really designed for this. It struggles to accept the capture footage unless the quality is set really low and it's not a gaming laptop so the graphics card is obviously under stress but I'm actually impressed at how is coped so far. Opening software can take forever and it takes a long long time for my video editing software to render a 20 minute YouTube video. I can't afford to replace the laptop so had considered looking at upgrading the processor and/or ram but then someone told me to consider trying replacing my HDD with SDD because that could speed it up enough. So a couple of questions....
Firstly.... Is this a good bit of advice?
Secondly, I have a 1tb HDD but could only afford maybe a 240gb SDD, soooooo... Is there any way of using the HDD as external storage afterwards?

As you can probably tell from my limited terminology, I'm far from a computer expert. I'm more of a dad trying to do the best i can for my kid on a limited budget. So any advice and help would be hugely appreciated.
The details of my laptop are....

HP NOTEBOOK
Intel(R) Pentium(R) CPU N3710@ 1.6GHz
4gb RAM
64bit
Running Windows 10 Home

Thanks very much.

 

[ColinLaybourn]

Thanks for the quick reply guys. I'll definitely look into the caddy/enclosure. Andy, I figured as much about the video rendering but to be honest, I can live with that as long as I can make the programs quicker and more responsive overall. I'll worry about a full upgrade when he's a famous YouTuber and pays me a decent wage

 

[ColinLaybourn]

I appreciate the advice. The laptop was a gift from my brother so I didn't really get a say in where it came from. At the time I only needed it for my writing.
Like I said, I can live with it taking ages to render video, I just leave it alone until it's done. Being able to access files quicker than the 4 minutes it currently takes to open my video folder, would be a massive help.
I take your comments on board though. Does anyone happen to know whether I could add any ram to this machine until I can consider any kind of new computer?