WiFi signal strength

Of this is the wrong place apologies

I'm looking to see of its possible to improve my wifi signal strength.
I'm using a Chromecast and the signal strength isn't great which means the media playback is a bit jittery.
How can I impact the signal strength and quality positively.
I've been told using an old router as an access point may be an idea?

Router stats:

StatusTxPktsRxPktsCollision PktsTx b/sRx b/sUp TimeWANPPPoA91846714152390569285568:50:38LANDown00 00000:00:00WLANUp54526904138708158900128:16:57Broa dband LinkDownstreamUpstreamConnection Speed13772 kbps1278 kbpsLine Attenuation30.0 dB16.9 dBNoise Margin6.2 dB4.4 dB

WiFi analyser signal strength graph:

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