When I try to log into our church's website I get a message from Avast saying that it is Malware.
if you mean URL:mal ... it means the url is on a blacklist for whatever reason.... does not have to be infected

this may be a general IP block ?

see here http://urlquery.net/report.php?id=6795542
see Recent reports on same IP/ASN/Domain you find several websites using same IP that have IDS alerts from Suricata / Snort filter
like this one http://urlquery.net/report.php?id=5756468 / http://urlquery.net/report.php?id=5279188

IP is also listed at l2.apews.org blacklist

[b]l2.apews.org[/b]

Level 2 lists IP addresses and netblocks of known spammers, anyone who is spam-friendly, or more worse supporting spammers. Listing starts at single IP’s and can escalate up till the entire netrange of a spammer or spam supporter is listed. The Level 2 list will have some inadvertent blocking (non-spammer IP addresses included in listed blocks), but can still be used by small ISPs or individuals who want a stricter level of blocking/filtering. By having a two style list, you can make the hardcore spamfighters happy; those who want to block first and ask questions later. Also, a listing in the Level 2 list may exert a bit of pressure on spam friendly sites and may keep them from turning totally bad - but that is not really the point, stopping spam is.