How to get latest version of Google Play Store
If you don't trust other sites, then use Yalp.

Yalp Store lets you download apps directly from Google Play Store as apk files. It can search for updates of installed apps and lets you search for other apps. Yalp saves downloaded apks to your default download folder. Other features include browsing categories, viewing and leaving reviews, black/whitelisting apps for updates, filtering apps by being free/paid and containing/not containing ads.
To supplement the features related to Google Play, Yalp Store has ordinary package manager features: listing, running, installing and uninstalling local apps

Also, visit What are the alternative Android app markets? to get a list of other apps/places/sites that can help you get it.