You are certainly a good friend!
I too am concerned about antifreeze. It is lethal and in an average cat, only a few licks can shut down the kidneys. Within an hour of ingestion, they can act drunk, then they seem to get better, then the kidneys are affected and they usually go downhill very rapidly after that. There is a test for antifreeze ingestion but no cure. Sometimes if they only ingest a small amount, several days of hospitalization on IV fluids can help, but they will still have some kidney damage. Unfortunately, all of this would mean a trip to the vet asap and I know you mentioned you don't have a lot of funds available.
Some other things that could cause this behavior would be atypical seizures, a stroke, a very high fever with resulting central nervous system damage, encephalitis, etc. I have also seen very strange behavior with some of the cheap flea treatments that are available.
An injury could also account for these signs and may explain the weakness as well as the behavior changes (head trauma).
Unfortunately, the best thing to do would be to have her seen as soon as possible. There is a company that will give a small loan just for veterinary expenses. Some clinics accept this and you can apply at the clinic or even on line. If approved, the funds are available immediately and then you make payments to the company. Try www.carecredit.com. You can call a 24 hour clinic in your area to see if they accept this.
If there is no way to have her seen, just continue to offer her fluids. Unflavored pedialyte is great at preventing dehydration but it would likely need to be slowly syringed to her as most cats won't willingly drink it. Keep her indoors for the next few days and watch her closely.
You could gently run your fingers through her fur over every single part of her body to check for small scabs or scrapes that might indicate an injury.
You could also check her rectal temp using a digital thermometer. Cats should be between 100.5 and 102.5 degrees.
Let her eat if she wants but don't force her. Offer her some canned food if you only feed dry. This is the current recommendation for all cats (www.catinfo.org).
Watch very closely for normal urine and stool in the next 24 hours. Sometimes if there is blood in the urine, you can see this by placing some white paper in the bottom of her litter box with only about 1/2 to 1 inches of litter on top. If the blood is significant, you may be able to see pink on the paper.
Do not give her any medications from home as almost all human drugs are extremely toxic in cats.
I hope this helps give you some options. Please let me know if you need anything else.