To import comments into HyperCommets system you need to create a file with the comments in XML format and upload it in administrative section of the website: "Settings" -> "Import\Export" -> "HC icon".

File format for import:

<?xml version="1.0" encoding="UTF-8"?>
<hc>
<post>
	<title>Page name</title>
	<url>test.com/10/23/2013/test/</url>
	<xid>test.com/?p=1</xid>
	<stream_id>51b1e59177e3146f63000003</stream_id>
	<comments>
		<comment>
			<id>1370613151388748</id>
			<parent_id/><root_id/>
			<text>Comment text</text>
			<nick>Ivan Ivanov</nick>
			<time>Fri, 07 Jun 2013 13:52:31 GMT</time>
			<ip>218.117.64.236</ip>
			<email/>
			<account_id>1</account_id>
			<files>
				[
					{"type":"images","service":"internet","href":"http://test.com/images/user_1/1370613863_4.jpg"},
					{"type":"video","service":"youtube","href":"http://www.youtube.com/watch?v=C4sNDn20olw4"},
					{"type":"presentation","service":"google","href":"https://docs.google.com/presentation/embed?id=1aCR4w0BwoqBSolE9TQv_assda"}
				]
			</files>
			<vote_up>0</vote_up>
			<vote_dn>3</vote_dn>
			<topic>false</topic>
			<param/>
			<hc_comment>false</hc_comment>
			<avatar>http://test.com/images/user_1/photo.jpg</avatar>
			<category>2</category>
		</comment>
		<comment>
			<id>1370613160711166</id>
			<parent_id>1370613151388748</parent_id>
			<root_id>1370613151388748</root_id>
			<text>Comment text</text>
			<nick>Ivan Ivanov</nick>
			<time>Fri, 07 Jun 2013 13:52:40 GMT</time>
			<ip>217.117.64.236</ip>
			<email/>
			<account_id>1</account_id>
			<files/>
			<vote_up>0</vote_up>
			<vote_dn>0</vote_dn>
			<topic>false</topic>
			<param/>
			<hc_comment>false</hc_comment>
			<avatar/>
			<category/>
		</comment>
		<comment>
			<id>1370613240522627</id>
			<parent_id/>
			<root_id/>
			<text>A piece of text</text>
			<nick>Ivan Ivanov</nick>
			<time>Fri, 07 Jun 2013 13:54:00 GMT</time>
			<ip>217.117.64.236</ip>
			<email/>
			<account_id>1</account_id>
			<files/>
			<vote_up>0</vote_up>
			<vote_dn>0</vote_dn>
			<topic>true</topic>
			<param>{"text":"A piece of text","position":63,"start_node":"9","end_node":"9","start_offset":"149","end_offset":"154"}</param>
			<hc_comment>false</hc_comment>
			<avatar/>
			<category/>
		</comment>
		<comment>
			<id>1370613240522632</id>
			<parent_id>1370613240522627</parent_id>
			<root_id>1370613240522627</root_id>
			<text>Hypercomment</text>
			<nick>Ivan Ivanov</nick>
			<time>Fri, 07 Jun 2013 13:54:00 GMT</time>
			<ip/>
			<email/>
			<account_id>1</account_id>
			<files/>
			<vote_up>0</vote_up>
			<vote_dn>0</vote_dn>
			<topic>false</topic>
			<param/>
			<hc_comment>true</hc_comment>
			<avatar/>
			<category/>
		</comment>
	</comments>
</post>
</hc>

, where