So you've applied for an extension? Any news on that yet? It's good you're being proactive about the situation.
Yes, it's important to be careful because IRCC can be very strict with the way they apply the rules, and you don't want to risk their ire.
In all honesty, it is easier for you to apply from outside Canada directly as a permanent resident than to change your status within Canada.
You should see if you can obtain 67 out 100 points for eligibility for the federal skilled workers program and then try to calculate your CRS.
You're in IT, which is always in demand in provinces like Ontario, so you can always look at PNP. I'd also look into the cost of a one year post-graduate diploma, you might just be able to swing it. You can then get a post-graduate work permit, by the time you accumulate all the bonuses for Canadian education and work experience, you'll have a lot of additional points for express entry. And as you said, you can save a lot by living with your relatives.